SUBMITTED TO:
AR. SHOBHIKA
Building construction
long span structure
SUBMITTED BY:
DHARNA GARG
B. ARCH. 7 SEM.
ROLL NO. 1221009
Introduction of hall of nation
BUT ABOVE ALL, TO REFLECT SYMBOLICALLY AND TECHNOLOGICALLY, INDIA'S
INTERMEDIATE TECHNOLOGY IN THE 25TH YEAR OF ITS INDEPENDENCE.
THE DEPTH OF THE STRUCTURAL SYSTEM WAS UTILIZED AS A SUN BREAKER AND CONCEIVED OF IN TERMS OF THE TRADITIONAL 'JALI',
A GEOMETRICAL PATTERN OF PERFORATION THAT SERVES TO OBSTRUCT DIRECTS RAYS OF THE HARSH SUN WHILE PERMITTING AIR CIRCULATION.
THE MAIN PAVILION OF THE HALL OF NATIONS HAS A CLEAR SPAN OF 78 METRES AND A HEIGHT VARYING FROM THREE METRES TO 21 METRES,
THEREBY PROVIDING A VAST CAPACITY FOR ITEMS TO BE EXHIBITED, FROM
BOOKS TO BULLDOZERS.
THE PERMANENT EXHIBITION
COMPLEX IS DESIGNED TO FORM THE FOCUS OF 130 ACRES OF EXHIBITION
GROUND DESIGNED BY RAJ REWAL IN NEW DELHI.
THE DESIGN WAS EVOLVED TO MEET THE CONSTRAINTS OF TIME, AVAILABILITY OF MATERIALS AND LABOUR,
LOCATION: NEW DELHI, DELHI, INDIA
PROJECT COMPLETED: 1972
AN INTERNATIONAL TRADE
FAIR TO BE HELD AT NEW DELHI IN 1972, REQUIRED LARGE
EXHIBITION HALLS.
THE MAIN HALL IS REQUIRED TO
HAVE A FREE AND UNOBS TRUCTED SPACE
OF 670 SQ. M. WITH AN APPROPRIATE HEIGHT OF 30 M. AND WAS NAMED AS “HALL OF
SHAPE AND FORM
FOR COVERING SUH A LARGE AREA
SEVERAL OPTIONS E.G. SHELLS, FOLDED
LATES, HYPAR SHELLS WERE CONSIDERD AND
REJECTED ON THE GROUND OF ECNOMICS.
EVENTUALLY THE SOLUTION NARROWED
DOWN TO A DOUBLE LAYERED SPACE FRAME..
THE HALL OD DIMENSIONS HAVE A BASE DIMENSION OF 73 M X73 M. WHICH REDUCED
TO ALMOST HALF AT THE ROOF.
WHILE THE INVESTIGATING THE
CONFIGURATION OF SPACE FRAME IT WAS IDENTIFIED THAT THE MOST APPRORIATE SYSTEM TO CREATE SPACE FRAME WAS THE ONE WHICH USED PYRAMID AS A BASIC ELEMENT.
STEEL AND CONCRETE WERE GIVEN
DUE CONSIDERATION AND IT WAS FOUND THAT CONCRETE WAAS THE MST ECONOMICAL MATERIAL , WITH STRUCTURAL STEEL BEING 30% MORE EXPENSIVE.THUS CONCRETE WAS THE FINAL CHOICE.
FOR CLADDING, GUNITED TRIANGULAR PLATES WERE PROVIDED WHILE ROOF
OF THE HALL WAS COVERED WITH THE PRECAST LIGHT WEIGHT CONCRETE PLANKS.
A STUDY OF THE CONFIGURATION
REVEALED TE STRUCTURE WOULD BE STABLE ONLY AFTER CONSTRUCTION HAD REACHED AT LEVEL , WHERE IT RECEIVED THE FIRST AROUND
CONTINUITY AND BEFORE THAT IT WOULD REST ON SCAFFOLDING ERECTED FROM GROUND.
DESIGN AND ANALYSIS
HOWEVER THIS RESULTED IN FIVE
DIFFERENT CONFIGURATIONS WITH INTRODUCTION OF EACH ADDITIONAL RING BEYOND LEVEL 5. THEREFORE ANALYSIS WAS CARRIED OUT FOR ALL FIVE DIFFERENT CONFIGURATION TO FIX FINAL MEMBER SIZES
THE ANALYSIS
WAS DONE ASSUMING PINNED JOINTS , AS THE MEMBER WERE SLENDER AND IT WAS BELIEVED THAT SIGNIFICAT MOMENTS WOULD NOT DEVELOPED .AN INDEPENDENT ANALYSIS DONE LATER CONFIRMED
THIS ASSUMPTION AS THE MOMENTS IN MEMBERS VERY SMALL.
THE SPACE FRAME WAS ANALYSED FOR
EARTHQUAKE AND WINDLOADS USING A THREE DIMENSIONAL PLAN JOINTED MODEL.MOST
IMPORTANT POINT FOR
SELECTING A MEMBER SHAPE
WAS STRENGTH AND EASE OF FABRCATION
.SEVERAL ALTERNATIVES FOR MEMBERS SECTION
WERE CONSIDERED AND FINALLY
A RHOMBIC SECTION
WITH CHAMFERED EDGES HAVING AN AREA OF 585
SQ. CM WAS ADOPTED
THE ANALYSIS WAS REVELEAD THAT
HORIZANTALL
REFELCTIONS OF NODES NEAR CENTRAL LINES
SYMMETRY WOULD BE LARGE
. TO CONTAIN THERE REFLECTIONS, HORIZANTALL
DIAPHRAGMS WERE INTRODUCED BETWEEN INNER AND OUTER FACES OF THE SPACE FRQAME AT LEVEL 3,6,8.
DESIGN AND ANALYSIS
THE OBVIOUS CHOICE OF CONSTRUCTION
WAS PRECAAST CONSTRUCTION
TECHNIQUE . IT WAS VISUALLISED THAT THE
MEMBERS AND JOINT WOULD BE PRECAST SEPERATELY AND PUT TOGETHER WITH HELP OF BOLTS AND FILLED WELDING OF SHIM PLATES .
DETAILS OF SUCH PRECAST JOINT ARE
SHOWN IN FIG. UNFORTUNATELY NO CONTRACTOR CAME FORWARD TO CONTSRUCT THIS STRUCTURE USING PRECAST TECHNIQUE ,
HENCE INSITU CONCRETE WAS ADOPTED .
THE DEVELOPMENT OF INSITU JOINT WAS DIFFICULT OWING TO
CONGESTION OF
BARS AT THE JOINT ELEMENT . ON AN
AVG. , 9 MEMBERS MET AT ONE JOINT
AND EVEN WITH 4 BARS PER MEMBERS
,DESIGN AND ANALYSIS
FINALLY A SYSTEM WAS EVOLVED WHERE
ONLY 20 BARS PASSED THROUGH THE JOINT
ELEMENT .BARS FROM LOWER 4 MEMBERS WERE LAPPED WITH 4 UPPER MEMBERS BARS THUS CATERING TO 8 MEMBERS .
THE SEQUENCE OF CONSRUCTION WAS TO
CAST STRAIGHT LENGTH OF MEMBERS FROM JOINT TO JOINT , PLACE IN POSITION PARTIALLY PREASSEMBLED FORM WORK OF THE JOINT ALONG WITH PLACED IN
POSITION SHORT LENGTH CURVED BARS .T
THESE BARS WERE WELDED WITH
STRAIGHT BARS OF MEMBERS , FORMWORK OF THEMEMBER UPTO NEXT JOIT ERECTED AND THE MEMBER AND THE JOINT
CONCRETED .
THIS SEQUENCE WAS FOLLOWED UPTO
ROOF LEVEL THE CONSTRUCTION OF
SPACEFRAME WAS TAKEN ON ALL 4 SIDES
SIMULTANEOUSLY .
THERE WOULD BE
36 BARS MEETING AT THE
JOINT
, SOME CARRYING TENSION WHILE OTHERS WERE IN COMPRESSION. IN THE PRECAST JOINT SOME ASSISTANCE WAS AVAILABLE FROM STEEL PLATES EMBEDDED INCONCRETE BUT IN THE INSITU JOINT THAT
Cross -section of Nehru
pavilion
plan
THE PLAN OF THESE PAVILIONS IS SQUARE WITH CHAMFERED CORNERS , PROVIDING
EIGHT ANCHORING POINTS.
THE CORNERS WERE INSPIRED BY THE TOMB OF MUGHUL EMPEROR HUMAYUN'S AND
THE TAJ MAHAL.
IN THE HALL OF NATIONS AN UNINTERRUTED VOLUME IS ACHIEVED WHERE THE HEIGHT VARIES FROM 3 M TO 30 M.
THIS PERMITS THE DISPLAY OF SUCH DIVERSE OBJECTS AS AIRCRAFT,
EARTHMOVING EQUIPMENT, TRACTORS AND CRANES.
IN THE HALL OF INDUSTRIES THE HEIGHT VARIES FROM 2.5 M TO 15 M. THE SQUARE