Bridge Data System. Structural Guide

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October 2009

Bridge Data System

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October 2009

1 Introduction

1.1 General

The purpose of this guide is to provide all users responsible for the preparation and maintenance of data for the Bridge Data System (BDS) with an understanding of the contents of the inventory and the requirements for updating the data.

1.2 Background Information

• large culverts (those with a cross sectional area greater than or equal to 3.4m2) The BDS is used for maintaining up-to-date structural information for all structures on the state highway network that are sensitive to overweight vehicle loads, and is used by OPermit to assist with the evaluation of overweight permit applications for travel on the State Highway network.

1.3 Structures to be included in the BDS

All bridges and culverts shall be included in the BDS, except for any culvert :

• _{that has a span of less than 2m,} • _{that has more than 1m of fill above,} • _{that has no unusual circumstances.}

The BDS is a NZ Transport Agency database designed to assist with the effective

management of bridge and culvert structures on the State Highway network, and contains all:

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1.4 BDS Structure

Bridge information is stored in a hierarchical structure as illustrated below.

Figure 1: BDS Data Structure

Each bridge/culvert is described by the General Bridge Data and is further represented by at least one of the underlying element types (Deck, TDeck, Beam etc.), which contain specific information about each element of the structure.

Element Description

GENERAL General information about the structure, including name, location, carriageway width etc. Form No.1 is to be filled out for all structures. DECK Used to model reinforced concrete deck slabs.

TDECK Used to model timber decks.

BEAM Used to model longitudinal components (as an equivalent simply

supported span) such as main beams or stringers where the components are of similar capacity and evenly spaced.

VBEAM Similar to BEAM elements but used where beams are asymmetrically spaced, are of differing capacities or there are discontinuities in the structure cross section.

TRANS Used to represent transoms.

INF For critical components (where BEAM elements are unsuitable), the overload effects are determined from influence lines.

CHECK CHECK elements comprise comments or instructions, and are used to augment structure data or outline specific actions required as part of the overweight permit process.

INTER Similar to INF elements but allows two longitudinal influence lines to be stored along with a capacity interaction diagram.

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1.5 Maintaining the BDS Data

It is vitally important that whenever a new bridge or culvert is constructed, or whenever existing structures are widened/replaced or their capacities are revised, the BDS is updated. The success of the BDS is dependant on the quality and completeness of the data it contains. The Regional Bridge Consultants are responsible for providing the information for input.

1.5.1 Modifying Existing Records

Where an update is related to an existing structure recorded in the BDS, a copy of the BDS report for that structure (available directly from the BDS or from regional hardcopy sets held by each Regional Bridge Consultant (RBC) and/or NZ Transport Agency Bridge Champion) should be marked up with the revised values/data and emailed to the National Office for updating.

1.5.2 Adding New Records

The first step in adding new records to the BDS is to determine how the structure is to be represented in the BDS. i.e. which element data is required to best model the structure. A General Bridge Data form (BDS Input Form No. 1) must be completed for every new structure. For each element used to represent a structure there is a corresponding data entry form that must be filled in to record the necessary data. A hard copy of each data entry form is included in Appendix A and is available from the BDS through the Forms Button in the Menu bar.

Examples of typical scenarios are included below:

Scenario Suggested Element Types

Evenly spaced beams and insitu r.c. deck slab

GENERAL, DECK, & BEAM Evenly spaced beams and timber deck GENERAL, TDECK, & BEAM

Box culvert GENERAL & BEAM

Armco Culvert GENERAL & BEAM

Slab GENERAL & BEAM or DECK

Truss, transoms, stringers and timber deck

GENERAL, TDECK, BEAM & TRANS

Box Girder GENERAL, BEAM & DECK

Widened bridges, asymmetric beam spacing, discontinuous decks

GENERAL, VBEAM & DECK Bridges with critical component such

as cantilever pier cap.

INF & element types as suggested above

Bridges with a specific Gross Weight limit (e.g. suspension bridges).

CHECK1 plus element types as suggested above.

Widened bridges where one lane is stronger than the remainder of the carriageway.

CHECK 2 plus element types as suggested above.

Arch bridges or bridges with critical components such as columns.

INTER plus element types as suggested above.

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1.6 Further Guidance

The purpose of this guide is to provide an understanding of the contents of the BDS and the requirements for updating the data. It has been prepared using the following

documents. Where further guidance is required it is recommended that these documents be referenced:

Bridge Overweight Rating and Posting Weight Assessment (TNZ Manual Number: SP/M/018) – June 2002

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2 Structural Element data production

The purpose of this chapter is to give a brief introduction to each element type and define the required information for each field on the data entry forms.

The importance of each field (i.e. mandatory, optional or default) is identified and, where applicable, the required units are noted.

Where applicable, reference has been made to other documents for a more in-depth explanation of how the expected data is calculated.

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2.1 Bridge General Data (BDS Structural Input Form No. 1)

For every new record added to the BDS, Input Form No. 1, Bridge General Data, must be completed. This form is used to record general data specific to the structure,

such as location, name, presence of bypasses etc.

BRIDGE GENERAL DATA FORM FIELDS LOCATION DATA

Bridge Name Mandatory

The name signposted on the bridge (usually the river or stream name), or if not signposted, the name by which the bridge is known.

If a signposted bridge is also known by an alternative name (if for instance the waterway and bridge have different names), this is shown additionally in brackets, e.g.:

INANGAHUA RIVER (REEFTON) BRIDGE

For Miscellaneous bridges (those structures that are adjacent to or pass over the SH and within the road reserve) the name will include the adjacent state highway in brackets, e.g.:

HIKURANGI CULVERT NO.2 (ADJ. SH1N) McEWAN ROAD OVERBRIDGE (OVER SH15A)

SH Code Mandatory

The relevant State Highway number. For bridges over or adjacent to State Highways, the highway is shown as MIS.

Route Position (RP) Mandatory

The Route Position (Reference Station plus Displacement) where the bridge is located, taken at the first abutment in the Increasing direction. For miscellaneous bridges the Route Position is the adjacent position on the State Highway.

BSN Mandatory

The Bridge Structure Number (BSN) is the (signposted) number assigned to the structure. The number must be sequential in the Increasing Direction and unique to the SH. The formula is BSN = (RS + Displacement)*10.

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Region Mandatory

NZTA region in which the structure is situated:

• 1- Auckland • 2- Hamilton • 3 - Napier • 4 - Wanganui • 5 - Wellington • 6 - Christchurch • 7 - Dunedin • 8 - Nelson • 9 - Marlborough Roads

Network Area Mandatory

The direction of traffic using the bridge. This may be:

• 1A – Northland

• 1B - Auckland North

• 1C - Auckland South

• 1D – Auckland Motorway Alliance

• 2A - West Waikato • 2B - East Waikato • 2C - Bay Roads • 2D - Tauranga District • 2E - PSMC 001 • 2F - Central Waikato • 2G - Rotorua • 2H - Bay of Plenty • 3A - Gisborne • 3B – Napier • 4A – West Wanganui • 5A - Wellington • 5B - Nelson • 5C – Marlborough Roads • 6A – West Coast • 6B – North Canterbury • 6C – South Canterbury • 7A – Central Otago • 7B – Coastal Otago • 7C – Southland

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Structural

Comments Optional

Structural Comments are messages to explain specific issues or requirements, or explain the reasons behind the modelling of the structural data.

Typical examples of Structural Comments are:

• “MCAP and SCAP specified for 3.5m width equivalent simple span”

• “Details of Deck Slab Span 2 not known”

• “Transverse Cross-Frames for Spans 1 to 3”

• “ECENTR is for truck central on southbound carriageway only, not full deck”

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BYPASS AND POSTING DATA

Direction Mandatory

The direction of traffic using the bridge. This may be:

•1 – Two Way (one, two or more lanes): traffic travels in both the Increasing and Decreasing Direction

•2 – One Way: traffic travels only in the Increasing Direction

•3 – One Way: traffic travels only in the Decreasing Direction

Bypass Type Mandatory

Indicates if a bypass is available for the bridge and the type of bypass. Bypass codes are:

• 0 – No bypass exists

• 1 – An off-highway bypass exists

• 2 – A bypass exists consisting of a bridge for traffic in the opposite direction

• 3 – Two forms of bypass exist – i.e. 1 and 2 above.

Bypass

Description Optional

A brief description of the off-the highway bypass. E.g. “Adjacent highway ford available”.

Posted Speed Limit Mandatory

This is the legal speed limit (in km/h) applying to the bridge, which may be a value posted on the bridge, or the highway limit.

An entry of “None” indicates the open road limit and a value of 100km/h is assumed.

Posting Mandatory

The posted weight limit on the bridge as a percentage of Class

_Ι

(One). The posting must be a multiple of 10.If the bridge is not posted then enter “None”.

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Width Mandatory

The carriageway width of the bridge in metres to two decimal places between kerb faces or guard rails.

DCF Mandatory

The capacity of the most critical section of deck expressed as a proportion of the load effect produced by the rating load (Refer NZ Transport Agency Bridge Manual Second edition, Section 6.5).

DCF =

Increasing RestrictX Mandatory

The optimum transverse position (m) for the vehicle centreline, measured from the left hand carriageway edge in the Increasing highway direction.

K e r b o r G u a r d R a il K e r b o r G u a r d R a il V e h ic le C e n tr e li n e In c r e a si n g D ir e c ti o n RestrictX B r id g e C /L

Figure 2 – RestrictX Conventions

An entry of “0” indicates that the optimum position is central on the carriageway.

Decreasing RestrictX

For bridges with central median barriers where the optimum Increasing Restrict X values or Central Restrictions place the vehicle on the barrier, or on the opposing carriageway. Decreasing Restrict X is the optimum Decreasing highway direction transverse position (m) for the vehicle centreline, measured from the left hand Decreasing carriageway edge.

Overload wheel load capacity Rating load effect _min

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2.2 DECK Element Data (BDS Structural Input Form No. 2)

Deck elements are used to model reinforced concrete deck slabs. A number of different rectangular slab types are available, as indicated by the Type Code.

A number of different DECK elements may be input for a single bridge, with a separate data entry form being provided for each one.

DECK ELEMENT DATA FORM FIELDS

As defined previously (Refer 2.1)

Type Default

Always DECK

Description Mandatory

A brief description of the deck element being represented. E.g. “Edge deck slab spans 1-3” etc.

Impact Code Default

The impact code is used to identify the appropriate impact factors to be applied to the element at each restriction level.

Applications are generally as follows:

Impact Code Application

1 Timber

2 Concrete Deck Slabs

3 Main members other than timber (normal circumstances) 4, 5 Members subjected to abnormally severe impact

As DECK elements are used to model reinforced concrete deck slabs the Impact Code is always 2 for DECK elements.

Breadth Mandatory

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Length Mandatory

Longitudinal span of the concrete deck slab in metres to two decimal places.

Depth Mandatory

Slab thickness in metres to two decimal places.

Surface Mandatory

Depth of surfacing/fill on the slab in metres to two decimal places.

Type Code Mandatory

Defines the edge conditions of each deck element. Possible Type Codes are: 1 = all edges encastre (interior slab)

-1 = all edges simply supported 2 = edge 3 free, other edges fixed

-2 = edge 3 free, other edges simply supported 3 = edge 4 free, other edges fixed

-3 = edge 4 free, other edges simply supported 4 = edges 1 and 2 fixed, edges 3 and 4 free

-4 = edges 1 and 2 simply supported, edges 3 and 4 free 5 = edge 1 fixed, edge 2 simply supported, edges 3 and 4 free -5 = edge 1 simply supported, edge 2 fixed, edges 3 and 4 free

DECK ELEMENT No. i X Edge 1 Edge 2 E d g e 3 E d g e 4 Y Y' X' P o si ti v e H ig h w a y D ir e c ti o n ( L o n g it u d in a l)

Transverse Dire ction

Pos ition (i) Left hand kerb

pos ition (X=0)

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Subdiv Mandatory

Subdiv is used to determine the number of grid members, including the edge beams, spanning the longer span. This value is used to determine grillage layout for grid analysis of deck elements.

Pois Optional

Poisson’s Ratio. Default value is 0.15.

DCF Mandatory

The capacity of this deck element expressed as a proportion of the load effect produced by the rating load (Refer NZ Transport Agency Bridge Manual Second edition, Section 6.5).

DCF =

HTCAP Optional

Transverse overload hogging moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5) per unit width (kN.m/m).

HLCAP Optional

Longitudinal overload hogging moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5) per unit width (kN.m/m).

STCAP Optional

Transverse overload sagging moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5) per unit width (kN.m/m).

SLCAP Optional

Longitudinal overload sagging moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5) per unit width (kN.m/m).

Note:

If any of the variables HTCAP, HLCAP, STCAP or SLCAP are zero, it is assumed that the corresponding moments generated cannot be critical and hence need not be checked.

Values for at least one of these variables must be input.

Overload wheel load capacity Rating load effect

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Number Optional

The number of positions in which the deck element appears across the transverse bridge section. It is used in conjunction with the “Element Position” to determine the limits on the transverse positioning of the overweight vehicles on this element. If stored as zero with no “Element Position” values, then it is assumed that the vehicle may be positioned anywhere on the element to produce the worst possible results.

Element Position Optional

The ‘x’ co-ordinate values at which edge 3 of the element is positioned (See Figure 3).

Guard Optional

If there are two symmetrical edge slabs where Type Code is 2, -2, 3, -3, 4, -4, 5 or -5, then these can be covered by one element, by putting “Number” = 0 and

“Guard” = distance “a” from the outside slab edge to the edge of carriageway (positive).

The options for edge slabs are shown below:

Figure 4: Edge Slab Conventions

a a K er b o r G u a r d R a il K er b o r G u a r d R a il P o si ti v e D ir e c ti o n Width CASE 1 Two symmetrical edge slabs TYPE_CODE = 2,-2,3,-3, 4,-4,5 or -5 NUMBER = 0 Position = a (+ve) a K er b o r G u a r d R a il K er b o r G u a r d R a il P o si ti v e D ir e c ti o n Width CASE 2 LHS Edge Slab TYPE_CODE = 2,-2,4,-4, 5 or -5 NUMBER = 1 Position = a (-ve) K e rb o r G u a r d R a il K e rb o r G u a r d R a il P o si ti v e D ir ec ti o n Width CASE 3 RHS edge slab TYPE_CODE = 3,-3,4,-4, 5 or -5 NUMBER = 1 Position = a (+ve) a

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2.3 TDECK Element Data (BDS Structural Input Form No. 3)

TDECK elements are used to model all timber decks, whether spanning transversely or longitudinally.

A number of different TDECK elements may be input for a single bridge, with a separate data entry form being provided for each one

TDECK ELEMENT DATA FORM FIELDS

As defined previously (Refer 2.1)

Always TDECK

A brief description of the TDECK element. E.g. “200 X 100 TRANSVERSE PLANKS + 50 RUNNING PLANKS” etc.

The impact code is used to identify the appropriate impact factors to be applied to the element.

1 Timber

2 Concrete Deck Slabs

3 Main members other than timber (normal circumstances) 4, 5 Members subjected to abnormally severe impact Hence, the Impact Code is always 1 for TDECK elements.

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Type_Code Mandatory

This defines the type of deck. Available Codes are: 1 – Spanning Transversely

2 – Spanning Longitudinally

Span Mandatory

The effective span length of the TDECK element in metres taken as the clear distance between supporting members plus one half width of a supporting

member. This should not exceed the clear span between supporting members plus the element thickness.

MCAP Mandatory

This is the overload moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5.4) per unit width (kN.m/m). TDECK elements are analysed as simply supported elements. If the timber deck elements are

continuous over two or more spans, MCAP may be increased by 25% (provided live load moments are being calculated on a simple span basis). Ref. “Bridge Manual, 6.5.4 (a)”

The capacity used for comparison with calculated live load moments is MCAP multiplied by the distribution width identified by DIST_CODE below.

SCAP Mandatory

This is the overload shear capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.5.4) per unit width (kN./m). If shear is assumed not to be critical,

then enter as zero. The capacity used for comparison with calculated live load shear

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Plank Mandatory

The width of the plank for planked decks (DIST_CODE = 1, 2) or the depth of the deck for laminated decks (DIST_CODE = 3 to 6)

DIST_CODE Mandatory

This indicates the allowable distribution of a wheel load. Available codes are: 1 - Planks laid flat without running planks at least 50mm thick

2 - Planks laid flat with running planks at least 50m thick

3 - Nail laminated deck, fabricated in baulks, with no shear connection between them

4 - Nail laminated deck with end laminations well supported and either:

(a) Fabricated in baulks with shear connection between them by steel dowels or other means

(b) Fabricated in baulks and having running planks over them, more than 50mm thick

(c) Fabricated continuously in situ across the span, with no unconnected joints between laminations

5 - Glue laminated deck, fabricated in baulks with no shear connection between them

6 - Glue laminated deck, otherwise as 4 (a), (b) or (c)

These codes correspond with the Bridge Manual, 6.5.4 (a), (i) to (vi).

Number Mandatory (Type_Code 1 only)

For elements with Type_Code 1, the number of positions in which the element occurs across the transverse bridge section.

This is used in conjunction with Position to determine the limits on the transverse positioning of the overweight vehicles on this element. If stored as zero, then it is assumed that the vehicle can be positioned anywhere on the element to produce the worst possible effects.

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Position Optional

The ‘x’ coordinate at which edge 3 of the element (as illustrated below) is positioned. TDECK Ele me nt No. i X Edge 1 Edge 2 E dg e 3 E dg e 4 Y Y' X' P o si ti v e H ig h w a y D ir ec ti o n

Transve rse Dire ction

Position (i) Le ft hand ke rb

position (X=0)

Figure 4: TDeck Element Conventions

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2.4 BEAM Element Data (BDS Structural Input Form No. 4)

BEAM elements are used to model longitudinal components such as main beams and stringers.

A number of different BEAM elements may be input for a single bridge, with a separate data entry form being provided for each one

Each element is represented as a simply supported beam with an eccentricity factor to allow for transverse distribution effects.

BEAM ELEMENT DATA FORM FIELDS

Always BEAM

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The effect of applying increasing restrictions is to reduce the impact factor. The impact factor of any restriction level is calculated in accordance with the stored impact code as follows:

Impact Code Equation

1 I = 1.0

2 I = (1.0 + 0.1Kv)Ks

3 For shear, I = (1.0 + 0.1Kv)Ks

For moment, I = min of (1.0 + 0.1Kv)Ks and,

(1.0 + 5Kv/(L+38))Ks

4 I = (1.0 + 0.15Kv)Ks

5 For shear, I = (1.0 + 0.15Kv)Ks

For moment, I = min of (1.0 + 0.15Kv)Ks and,

(1.0 + 7.5Kv/(L+38))Ks

Where I = Impact Factor,

L = Span of the element in metres Kv = a function of truck speed

Ks = a function of truck speed

Values of Kv used in the impact equations are:

Vehicle Restriction Restriction Level Kv Ks

Unrestricted -1 3 1.1

50 km/h Own Lane 0 3 1.0

20 km/h Own Lane 1 2 1.0

Crawl Own Lane 2 0 1.0

Crawl Central 3 0 1.0

1 Timber

Hence, the Impact Code for BEAM elements may be 1, 3, 4 or 5 depending on the material and/or impact conditionsThe effect of applying increasing restrictions is to reduce the impact factor. The impact factor of any restriction level is calculated in accordance with the stored impact code as follows:

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ESTD Mandatory

The eccentricity factor is defined, for beam and slab bridges as:

ESTD(Beam bridge) = Moment in most heavily loaded beam (or truss)

Average moment per beam (or truss) and

ESTD(Slab bridge) = Peak moment per metre width

Average moment per metre width

The carriageway shall normally be divided into lanes as defined in the NZ Transport Agency Bridge Manual, but in the case of a multilane bridge carrying traffic in one direction only, shoulders may be excluded from the carriageway.

Wide slab, short span structures (e.g. short span multi-lane box culvert) may be represented as a 3.67m wide strip with ESTD = 1.0

For single lane bridges, ESTD shall be calculated with the load at extreme eccentricity in the lane as defined in the Bridge Manual.

For two, three or four lane bridges, ESTD shall be calculated for the condition of two lanes loaded. The loads in the two lanes shall be:

- In one lane, 85% of one element of HN-72 loading, and

- In one other lane, 85% of one element of HO-72 loading.

Both load elements shall be placed at extreme eccentricity in the lane, as defined in the Bridge Manual. The lanes to be loaded shall be chosen so as to produce the worst effect.

Ideally the eccentricity factor should be determined using a method which takes into account the relative stiffness of longitudinal and transverse members. For bridges of one or two lanes, the simplified method given in AASHTO “Standard Specifications for Highway Bridges” may be appropriate. For bridges wider than two lanes and for those cases where AASHTO is not appropriate, a more rigorous analysis such as a computer grillage analysis should be carried out.

ECENTR Mandatory

This is the eccentricity factor with the vehicle central on the bridge, or at such other position (RestrictX) so as to maximise the allowable vehicle load.

ECENTR shall be calculated for the condition of 85% of one element of HO-72 loading being the only load on the structure.

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Longitudinal span length of the element (m)

This is the overload moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, Section 6.4.2) of the total bridge cross-section (kN.m). Note: For continuous or framed-in beams, MCAP must be the overload moment capacity of an equivalent simply supported member. Where beams have full

moment continuity between spans, are of normal proportions and show no signs of distress, the following simplified procedure may be followed:

The overall moment capacity of each span may be converted to that of an

equivalent simple span by subtracting (algebraically) the midspan positive moment capacity from the mean of the two negative moment capacities at its supports.

This is the overload shear capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, Section 6.4.2) of the total bridge cross-section (kN).

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2.5 VBEAM Element Data (BDS Structural Input Form No. 5)

VBEAM elements are similar to BEAM elements except that, instead of combining all of the longitudinal beams (or stringers) together and representing them as a single simply supported beam, each beam is considered in its actual position and assigned its own simply supported moment and shear capacities.

This allows the inclusion of beams with different capacities and asymmetrical or uneven beam positioning with respect to the carriageway (E.g. widened and multi span bridges). These elements need not occupy the complete carriageway width. Two or more elements may be used to represent the total cross section if, for instance, the span lengths of the parts are different.

Discontinuities (zero moment and/or shear capacity) in the transverse structure of the deck, which may be due to bridge widening, can also be included.

VBEAM ELEMENT DATA FORM FIELDS

Always VBEAM

A brief description of the VBEAM element. E.g. “OLD 2 BEAM STRUCTURE + WIDENING COMPRISING 11 PSC UNITS”.

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Impact Code Mandatory

Applications are generally as follows: Refer 2.4 for definition of Impact Code.

1 Timber

The Impact Code for VBEAM elements may be 1, 3, 4 or 5 depending on the material and/or impact conditions.

Longitudinal span length of the element in metres

NBEAMS Mandatory

Number of longitudinal beams

NDISC Mandatory

Number of discontinuities (may be zero).

Discontinuities may be used in a number of ways:

If the position of a discontinuity is given within ±0.01m of a beam position, the superstructure at that beam is taken as having a small moment capacity for moment distribution and the full reaction obtained by treating the deck as simply supported at the longitudinal beams is used at that beam.

If a discontinuity is positioned between beams, this is taken to represent a complete break in the superstructure at this point, and loads have no effect across the break.

If a discontinuity is positioned before the first beam or after the last beam, this indicates that the full extent of the element and any load outside these

discontinuities does not affect the element.

The distribution of loading to the first and last beams and all beams adjacent to a discontinuity is taken as the full reaction from the simply supported deck. Any interior beam not associated with a discontinuity takes a loading of 0.8 times the simply supported reaction.

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This is the overload moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.4.2) of each beam (kN.m).

Note: For continuous or framed-in beams, MCAP must be the overload moment capacity of an equivalent simply supported member. Where beams have full moment continuity between spans, are of normal proportions and show no signs of distress, the following simplified procedure may be followed:

The overall moment capacity of each beam may be converted to that of an equivalent simple beam by subtracting (algebraically) the midspan positive moment capacity from the mean of the two negative moment capacities at its supports.

The overload shear capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.4.2) of each beam (kN).

If shear is assumed not to be critical, then enter as zero.

XPosition Mandatory

The distance to each beam centre in metres from the left hand kerb or guard rail (when looking in the increasing highway direction).

Position of

Discontinuities Mandatory

The distance of discontinuities in metres from the left hand kerb or guard rail (when looking in the Increasing highway direction).

x1 x2 x3 x4 x5 P osit ion of discont inuit y Original single lane bridge

Discont inuit y bet ween original and new deck

Deck widened using P SC Hollow core beams

xi = XPosition

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2.6 TRANSOM Element Data (BDS Structural Input Form No. 6)

TRANSOM elements are used to represent transoms (i.e. transverse beams, supported at two points, which support longitudinal beams or stringers. The TRANSOM element also includes any portion of the transom cantilevering beyond the support points.

Positive and negative capacities are assumed to be the same and the carriageway centreline is assumed to coincide with the centreline of the supporting beam system.

TRANSOM ELEMENT DATA FORM FIELDS

Always TRANSOM

A brief description of the TRANSOM element. E.g.“TRANSOMS SPANS 1 AND 4”.

Applications are generally as follows: .

1 Timber

The Impact Code for TRANSOM elements may be 1, 3, 4 or 5 depending on the material and/or impact conditions.

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TSpan Mandatory

The length of the transom in metres between supports.

SSpan Mandatory

The span length of the longitudinal stringers supported by the transom in metres

The overload moment capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, Section 6.4) of each transom (kN.m) for an equivalent simply supported span.

The overload shear capacity (as defined in NZ Transport Agency Bridge Manual Second Edition, 6.4) of each transom (kN) for an equivalent simply supported span.

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2.7 INFLUENCE Element Data (BDS Structural Input Form No. 7)

INFLUENCE elements are used in a similar manner to the BEAM elements, except that instead of calculating the truck effects on a simply supported span, the effect is determined from a longitudinal influence line of arbitrary shape. This allows components, for which it may not be appropriate to use an “effective simply supported span” (e.g. pier caps, cantilevered spans etc.), to be checked against an overload.

The influence line applies to a fixed point on the bridge and to only one effect (e.g. only moment or only shear). Therefore only one capacity is stored for comparison. Two scale factors are provided, one for when the truck is central and one for when it is in its own lane. Changes in the magnitude of the influence line in these situations can thus be accounted for.

A number of different INFLUENCE elements may be input for a single bridge, with a separate data entry form being provided for each one.

The analysis for this element type is similar to that for a BEAM element except that instead of finding the maximum moment and shear on a simply supported span, the truck is positioned on the stored influence line to give the maximum effect.

The basic overload effect (i.e. overload moment or overload shear) is multiplied by a scale factor – either BSTD for the truck in its own lane or BCENTR for the truck central. BSTD is equivalent to ESTD for a BEAM element on a single lane bridge and to ESTD(1 + 1/KBASIC)

for a BEAM element on a bridge with two or more lanes, where KBASIC is the ratio MHO/MHN.

BCENTR is equivalent to ECENTR for a BEAM element.

The basic overload effect, when multiplied by the scale factor and impact factor, is compared with the stored capacity, CAPAC to determine the appropriate restriction level. No account is taken of traffic in an adjacent lane by this analysis, unless an adjustment is made to BSTD as described above.

INFLUENCE ELEMENT DATA FORM FIELDS

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A brief description of the INF element. E.g. “TRANSVERSE CANTILEVER BEAMS - ALL SPANS”.

1 Timber

3 Main members other than timber (normal circumstances) 4, 5 Members subjected to abnormally severe impact Refer 2.4 for definition of impact code.

The impact factor applicable to the restriction level being considered is calculated using the stored value of ‘YLength’ substituted for ‘L’.

The Impact Code for INFLUENCE elements may be 1, 3, 4 or 5 depending on the material and/or impact conditions.

StressNo Mandatory

Identifies the overload effect being represented by the INF element. Stress No Overload Effect 1 Moment 2 Shear BSTD Mandatory

The scale factor when the truck is in its own lane.

BCENTR Mandatory

The scale factor when the truck is central.

YLength Mandatory

The span length used for calculating the impact factor (m).

CAPAC Mandatory

The capacity (moment or shear) used for comparison at the location represented by the influence line (kN.m or kN).

Number Mandatory

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YPosition Mandatory

Used to record the influence line position ordinates (m) from an arbitrary origin, in the longitudinal direction along the bridge deck.

Influence

Coefficient Mandatory

Influence coefficients (kN.m/kN.m for moment or KN/KN for shear) corresponding to the position ordinates.

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2.8 CHECK Element Data (BDS Structural Input Form No. 8)

CHECK elements are messages to either augment the structural elements, explain specific requirements, or alert users to specific issues.

2.8.1 CHECK 1 Elements

Where a CHECK 1 element is present, this is highlighted each time an Overweight Permit is processed for that bridge. This is to alert the Permit Officer and HMV driver to specific requirements of the permit.

Typical examples of CHECK 1 elements are:

• _{Specific actions required as part of the overweight permit process, e.g. “NO}

STRUCTURAL DETAILS - REFER TO BRIDGE CONSULTANT”

• _{Bridges with a specific Gross Weight limit, e.g. “Max Gross Overload -}

Supervised 50,000kg Gross. No other HMV on Bridge”.

CHECK 2 elements are similar to CHECK 1 elements, but only apply where an overweight vehicle travels at Restriction Level 3 (i.e. 10 km/h Central or at offset RestrictX) on the bridge.

Where a CHECK 2 comment is recorded, this is highlighted each time an overweight permit results in Restriction Level 3 for that bridge. This is to alert the HMV driver to specific requirements of the permit.

A typical example of a CHECK 2 element is:

”VEHICLE CENTRELINE TO BE 4.1 M FROM UPSTREAM GUARDRAIL”

CHECK 3 elements are similar to CHECK 1 elements, but only apply where there is a specific condition that needs to be notified to an HMV driver.

Where a CHECK 3 comment is recorded, this is highlighted on an overweight permit regardless of whether there is a Restriction Level for that bridge. This is useful to highlight Posted Bridges without a specific Weight Limit, or to alert an HMV driver to specific

requirements for a bridge.

Typical examples of CHECK 3 element are:

• “MAX SPEED 20 KM/H. ONLY ONE HEAVY VEHICLE AT A TIME ON BRIDGE”

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2.9 INTER Element Data (BDS Input Form No. 9/9a)

INTER elements are similar to INF elements except that two longitudinal influence lines can be stored (moment and axial force) and, instead of a fixed capacity, a capacity interaction line (moment versus axial force), which defines an area of acceptable load effects, is stored.

The two influence lines apply to the load effects at a fixed point on the element. Two scale factors are provided, one for when the overload is central and one for when it is in its own lane. Changes in the magnitude of the influence line in these situations can thus be accounted for.

It should be noted that the interaction diagram is assumed to consist of either a single valued function, M(P), or two single valued function, M-(P) and M+(P), which represent the interaction curve for negative and positive moment respectively. The ordinate pairs can be entered in any order. The analysis program will reorder the pairs, and store them in order of increasing P, for each of the two possible functions. Storage of points for the M- curve is optional. If not stored, then, by default, M-(P) = - M+(P) is assumed.

A number of different INTER elements may be input for a single bridge, with a separate data entry form being provided for each one

The analysis for this element type is similar to that for an INF element except that two load effects (moment and axial force) must be accounted for at each incremental position of the overload on the bridge span, and, instead of computing a maximum load effect, the load effects at each incremental position, when multiplied by the scale factor and impact factor, are compared against the capacity interaction line.

The basic overload effects (i.e. moment and axial force) are multiplied by a scale factor – either BSTD for the overload in its own lane or BCENTR for the overload central. BSTD is equivalent to ESTD for a BEAM element on a single lane bridge. Since no account is taken of traffic in an adjacent lane by this analysis, BSTD is equivalent to ESTD(1+1/KBASIC) for a

BEAM element on a bridge with two or more lanes, where KBASIC is the ratio MHO/MHN.

BCENTR is equivalent to ECENTR for a BEAM element.

INTER ELEMENT DATA FORM FIELDS BDS Input Form 9 – Interaction Data

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Always INTER

A brief description of the INTER element. E.g. “RC ARCH Spans”.

Applications are generally as follows: .

1 Timber

3 Main members other than timber (normal circumstances) 4, 5 Members subjected to abnormally severe impact Refer 2.4 for definition of impact code.

The impact factor applicable to the restriction level being considered is calculated using the stored value of ‘Span’ substituted for ‘L’.

The Impact Code for INTER elements may be 1, 3, 4 or 5 depending on the material and/or impact conditions.

BSTD Mandatory

The scale factor when the truck is in its own lane.

BCENTR Mandatory

The scale factor when the truck is central.

The span length used for calculating the impact factor

Inter Mandatory

The number of points on the capacity interaction line.

Number Mandatory

The number of points on the influence line.

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PCAP Mandatory

The interaction line ordinates for axial force (kN) corresponding to the moment ordinates.

YPosition Mandatory

Used to record the influence line position ordinates (m) from an arbitrary origin, in the longitudinal direction along the bridge deck.

YPosition is recorded on BDS Input Form No. 9a

Moment

Coefficient Mandatory

The moment influence line coefficients (kN.m/kN) corresponding to the position ordinates.

Moment coefficients are recorded on BDS Input Form No. 9a

Axial Force Coefficient Mandatory

The axial force influence line coefficients (kN/kN) corresponding to the position ordinates.

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October 2009 35

APPENDIX A

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Bridge General Data – October 2009 Structural Input Form No. 1

BRIDGE GENERAL DATA (FORM No. 1)

Note: This data is required for all structures.

This sheet is accompanied by element data sheets.

LOCATION DATA Bridge Name SH Code Route Position BSN Region Network Area Structural Comment

BYPASS AND POSTING DATA

Direction 1 2 3 Bypass Type Bypass Description Posted Speed Limit km/h Posting Width m DCF RestrictX m Prepared: DATE: / / Checked: DATE: / /

Certified for Release: DATE: / /

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DECK Element Data – October 2009 Structural Input Form No. 2

DECK ELEMENT DATA (FORM No. 2)

Bridge Name

BSN Direction

DECK ELEMENT NO. OF

Type DECK Description Impact Code 2 Breadth m Length m Depth m Surface m Type Code Subdiv 9 Pois DCF HTCAP kNm/m HLCAP kNm/m STCAP kNm/m SLCAP kNm/m Number If Number > 0: Element Position OR If Number = 0 and

Type Code ≠ 1 or -1 Guard

m

PREPARED: DATE: / /

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TDECK Element Data – October 2009 Structural Input Form No. 3

TDECK ELEMENT DATA (FORM No. 3)

Bridge Name

BSN Direction

TDECK ELEMENT NO. OF

Type TDECK Description Impact Code 1 Type Code Span m TDeck MCAP kNm/m TDeck SCAP kN/m Plank m Dist Code Number If Number > 0 Element Position m PREPARED: DATE: / / CHECKED: DATE: / /

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BEAM Element Data – October 2009 Structural Input Form No. 4

BEAM ELEMENT DATA (FORM No. 4)

Bridge Name

BSN Direction

BEAM ELEMENT NO. OF

Type BEAM Description Impact Code ESTD ECENTR Span m BEAM MCAP kNm BEAM SCAP kN PREPARED: DATE: / / CHECKED: DATE: / /

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VBEAM Element Data – October 2009 Structural Input Form No. 5

VBEAM ELEMENT DATA (FORM No. 5)

Bridge Name

BSN Direction

VBEAM ELEMENT NO. OF

Type VBEAM Description Impact Code Span m NBeams NDisc

MCap SCap XPosition

kNm kN m Position of Discontinuities: m PREPARED: DATE: / / CHECKED: DATE: / /

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TRANSOM Element Data – October 2009 Structural Input Form No. 6

TRANSOM ELEMENT DATA (FORM No. 6)

Bridge Name

BSN Direction

TRANSOM ELEMENT NO. OF Type TRANSOM Description Impact Code TSpan m SSpan m Trans MCAP kNm Trans SCAP kN PREPARED: DATE: / / CHECKED: DATE: / /

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INFLUENCE Element Data – October 2009 Structural Input Form No. 7

Bridge Name BSN Direction

INF ELEMENT NO. OF

Type INF Description Impact Code StressNo Inf BSTD Inf BCENTRE YLength m CAPAC kNm or kN Number Influence Line

YPosition Influence Coefficient

m kNm/kN or kN/kN

PREPARED: DATE: / /

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CHECK Element Data – October 2009 Structural Input Form No. 8

CHECK ELEMENT DATA (FORM No. 8)

Bridge Name BSN Direction CHECK 1 CHECK 2 CHECK 3 PREPARED: DATE: / / CHECKED: DATE: / /

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INTER Element Data – October 2009 Structural Input Form No. 9

Bridge Name BSN Direction

INTER ELEMENT NO. OF

Type INTER Description Impact Code INTER BSTD INTER BCENTRE SPAN m Inter Number Interaction Diagram MCAP PCAP kNm kN PREPARED: DATE: / / CHECKED: DATE: / /

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INTER Element Data – August 2009 Structural Input Form No. 9a

INTER ELEMENT DATA (FORM No. 9a)

Bridge Name

BSN Direction

INTER ELEMENT NO. OF Influence Lines YPosition Moment Coefficient Axial Force Coefficient m kNm/kN kN/kN PREPARED: DATE: / / CHECKED: DATE: / /

Bridge Data System. Structural Guide