Vierendeel truss bs5

About Vierendeel Truss and its examples

1. 6. VIERENDEEL TRUSS Spurthi G Sandhya S Aadarsh

2. THE VIERENDEEL FRAME, or truss as it is more popularly but inappropriately called, is a series of rectangular frames which achieves stability by the rigid connection of the vertical web members to the top and bottom chord . Contrary to the typical pin-connected truss in which all members are axially loaded and shear is transferred axially through diagonals, the Vierendeel transfers shear from the chords by bending moments at the joints and finally by bending moments in the vertical webs. As a result, all members are combined stress members in which axial, shear, and bending stresses exist. INTRODUCTION

3. Such trusses do not have the usual triangular voids seen in a pin–joint  truss bridge , rather employing rectangular openings and rigid connections in the elements, which (unlike a conventional truss) must also resist substantial bending forces . Owing to a lesser economy of materials and the difficulty of design before the advent of computers, this truss is rarely used in bridges outside Belgium. The form is more commonly employed in building structures where large shear walls or diagonal elements would interfere with the building's aesthetics or functionality . The first such bridge was built in steel at  Avelgem ,  Belgium  in 1902, following development of the truss form and a method to calculate its strength in 1896 by  Arthur Vierendeel . There are many more examples in Belgium, also constructed in concrete, mostly designed by Vierendeel's many students in a long career as professor in  civil engineering .

4. Despite the structural disadvantages surrounding the Vierendeel, it was in the area of civil engineering rather than architecture that it was first utilized-specifically for short-span bridges. The Vierendeel's origin dates to I896. The Belgian engineer Arthur Vierendeel, then professor at the University of Louvain, unveiled the concept in his book Longerons en Treillis et Longerons a Arcades. At that time steel trusses required extremely large gusset plates to accommodate rivet groups; members were generally oversized and rarely did the center lines of all joined members intersect. Therefore, the pin-jointed theory which ignored moments, due to these eccentricities, led to errors on the critical side, approaching fifteen percent when office calculations were compared to field measurements. HISTORY

5. These discrepancies between simplified analytical methods and reality are what led Professor Vierendeel to propose the rectangular rigid-jointed system where these eccentricities could be eliminated and accuracy between analysis and reality kept in close accord. A smaller factor of safety could be used, due to this improved accuracy, so that in the early I900s Vierendeel bridges did weigh less than alternative truss solutions. The first Vierendeel bridge was experimental. It spanned 96 feet and was tested in 1897 at Tervueren with an assimilated railway loading pattern. The riveted framework responded by carrying 2.73 times the design live load and prompted the Belgian Bridge and Highway Department to state in their official report that, "In the present state of the question, the portal frame truss is, generally speaking, a system nearly equivalent to the triangulated truss.“ The first actual usage of a Vierendeel bridge occurred in I901 with a 128-foot span of riveted construction at Avelghem , Belgium, followed by the I36-foot span at Ousselghem in I910, also riveted.

6. Decline Mishaps (cracks and dislocations), primarily due to insufficient knowledge of the ramifications of welding procedures, poor workmanship, and low steel quality, resulted in increasing skepticism about the Vierendeel system . The collapse of a 245-foot-span bridge at Hasselt in 1938 was the most total and dramatic . A Belgian committee assigned to investigate the collapse, together with outside consultants, concluded that the welded Vierendeel system, although considered to be adequately designed, was sensitive to external influences, such as cooling, heating, vibration, or impact. By reason of its inherent joint rigidity, the system also attracted internal residual stresses and demanded an extensive knowledge of the art of welding. Similar problems with welded plate girder bridges were occurring in other countries of Europe. It was apparent that welding technology needed to catch up with welding demand DECLINATION

7. EXAMPLES

8. The Albert Canal was constructed from 1930 through 1939. The German construction company  Hochtief AG  worked on the canal between 1930 and 1934, but it was completed by Belgian companies. The Albert Canal was used for the first time in 1940 but, because of  World War II  and the  German occupation , intensive use only began later, in 1946. During World War II, the Albert Canal functioned as a defense line. The crossing of the canal by the German forces and the destruction of  Fort Eben-Emael  on 11 May 1940 was a milestone in the  German invasion of Belgium . During the Liberation of Belgium by the Allies in September 1944, the  Second Canadian Division  was the first Allied unit to cross the Albert Canal. The   British Army  also crossed the Albert Canal on its way north across Belgium and into  The Netherlands  and the  U.S. Army  entered Belgium further to the east on its way to liberate the rest of Belgium, and  Luxembourg , and then proceed east to invade  Nazi Germany .  Hence, Belgium was liberated from the south by three different armies, two of which needed to cross the Albert Canal. ALBERT CANAL

9. In 2002, the canal carried a record 43 million tons of goods of various kinds, amounting to more than half the Belgian waterway total.  The canal is also a popular leisure and cycling destination, with well paved service roads on both sides traversing picturesque farm land, particularly around Smeermass , Lanaken and Maasmechelen .

10. Vierendeel bridge at Grammene , Belgium

11. Geneva St. bridge in Glendale The city of  Glendale, California  has three Vierendeel truss bridges: the Geneva Street, Kenilworth Avenue, and  Glenoaks Boulevard bridges , all two-lane bridges spanning 95 feet. They were built in 1937 as part of the  Verdugo Flood Control Project , the first project of the  United States Army Corps of Engineers  after passage of the  Flood Control Act of 1936 . The double-deck cable-stayed  Kap Shui Mun Bridge in Hong Kong uses a Vierendeel truss. Opened in 1997, the lower deck carries both rail and traffic, with the lack of diagonal members in the cross section allowing vehicles to drive through the openings provided by the Vierendeel design.

12. Gutsav -Heinemann Brucke

13. BIBLIOGRAPHY REFERNCES The Vierendeel Author(s): David J. Wickersheimer Source: Journal of the Society of Architectural Historians, Vol. 35, No. 1 (Mar., 1976), pp. 54- 60 Published by: University of California Press on behalf of the Society of Architectural Historians Stable URL: http://www.jstor.org/stable/988971 . Accessed: 10/07/2013 10:19 Book: Building structures Author: Ching www.arch.mcgill.ca www.Wikipedia.com

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