Designing A Large Span Structures Under Seismic Loading – A Case Study

Abstract

Structural membranes have become a frequently preferred system type in long span structures such as amphitheatres, stadiums, performance centres, sport halls, with their ability to cover long distances by lighter solutions. The membrane material, which is the main component of the lightweight structures including membranes and has sufficient strength together with stretching, has very low weight of around 1 kg per sqm compared with the conventional load bearing materials. This is very important feature, both aesthetically and economically. Its light weight does not only provide an economical solution, but also allows to have better structural performance under seismic loads. Besides its lightness, another advantage of membrane-covered structures such as the amphitheatre is acoustic performance, which is an important one for the structure to meet serviceability requirements.

In this paper, the amphitheatre in Hasan Kalyoncu University in Gaziantep - Turkiye was chosen as a case study to show the design process of the membrane roof covering system supported by steel trusses under severe earthquake threats. This amphitheatre had some challenging features with its 94 m wide span arch and 5000 sqm covered area. It suffered three major earthquakes measuring: the first one 7.7 Mw (Richter Scale), 11 minute later second one 6.6 Mw and the third one after 9 hours (Mw) on the 6th of February 2023. The amphitheatre is only 50 km south of one of the epicentres of the largest earthquake. There were nearly 6.000 aftershocks within 10 days of the first earthquake. It is a relieve to see that the structure has not been affected. It was a relieve to see that there was no damage on the amphitheatre. However, the distraction effected 11 major cities, nearly 2 million people had to be relocated and more sadly around 45.000 people died. The devastation was catastrophic

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