Case Study of Long Span Structure

8/20/2019 Case Study of Long Span Structure

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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 OBSTRUCTDIRECTS RAYS OF THE HARSH SUN WHILE PERMITTING AIR CIRCULATION.

THE MAIN PAVILION OF THE HALL OF NATIONS HAS A CLEAR SPAN OF 78 METRES ANDA 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 NEWDELHI.

THE DESIGN WAS EVOLVED TO MEET THECONSTRAINTS 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

NATIONS”.



SHAPE AND FORMFOR COVERING SUH A LARGE AREA

SEVERAL OPTIONS E.G. SHELLS, FOLDEDLATES, HYPAR SHELLS WERE CONSIDERD AND

REJECTED ON THE GROUND OF ECNOMICS.

EVENTUALLY THE SOLUTION NARROWED

DOWN TO A DOUBLE LAYERED SPACEFRAME..

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 FIVEDIFFERENT 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 HORIZANTALLREFELCTIONS 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 OFBARS AT THE JOINT ELEMENT . ON ANAVG. , 9 MEMBERS MET AT ONE JOINTAND EVEN WITH 4 BARS PER MEMBERS ,



DESIGN AND ANALYSIS

FINALLY A SYSTEM WAS EVOLVED WHERE

ONLY 20 BARS PASSED THROUGH THE JOINTELEMENT .BARS FROM LOWER 4 MEMBERS WERELAPPED WITH 4 UPPER MEMBERS BARS THUSCATERING TO 8 MEMBER S .

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 WITHSTRAIGHT 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 IN

CONCRETE BUT IN THE INSITU JOINT THAT

WOULDNOT BE POSSIBL E .



Cross -section of Nehrupavilion

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 THEHEIGHT 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

PLAN ADOPTED PERMITS ADDITIOINAL UNITS TO BE ADDED AS NEEDED.

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Case Study of Long Span Structure