مطالعه عددي اثر زلزله و نشست تكيه‌گاه بر رفتار سازه‌اي طاق‌هاي ابرخشتي

Numerical Study of the Effect of Earthquakes an‎d Support Settlement on the Structural Behaviour of Superadobe Vaults

مهندسي عمران

Nowadays, the use of indigenous an‎d sustainable materials such as superadobe, as a novel approach in construction, has gained attention due to its environmental an‎d economic advantages. Superadobe structures, as a composite construction method using soil, bags, an‎d barbed wire, can provide a suitable solution for reducing costs an‎d building durable structures. However, the mechanical behaviour of these structures under various conditions, including static an‎d dynamic loads, requires comprehensive study an‎d analysis. The main issue of this research is to identify the effect of soil type, bag type an‎d thickness on the performance of mechanical properties of superadobe materials an‎d to investigate the effect of arch dimensions an‎d geometry, the role of the wall an‎d the dimensions an‎d geometry of the opening on the performance of the structure under the effect of support settlement an‎d earthquake. This research includes experimental tests an‎d numerical analyses. In the experimental section, the effect of soil type an‎d bag on the mechanical behavior of superadobes was investigated. The results showed that clayey gravel soil creates significantly more flexural an‎d compressive strength than poorly graded san‎d; so that the average flexural bearing capacity an‎d compressive strength of samples made with clayey gravel soil increased by up to 347% an‎d 9.11% respectively compared to samples made with poorly graded san‎d soil. Also, the use of a bag with a greater thickness created a significant improvement in flexural an‎d compressive strength, but the results showed that the effect of soil type on the overall strength of the superadobe is greater than the type an‎d number of bag layers. In numerical analyses, the behaviour of superadobe arches made with the cross-section of dro‎p, ordinary an‎d raised pointed arches was investigated under support settlement an‎d earthquake conditions. In different arches, the effect of the absence of a wall, the presence of a wall on one side of the arch, an‎d the presence of a wall on both sides of the arch on the performance of the structure during settlement was investigated. Arches without walls an‎d arches that have walls on both sides showed better performance under the effect of support settlement than arches that had walls only on one side. Arches without walls showed at least 50% an‎d arches that have walls on both sides, at least 4.7% better performance compared to arches that have only one wall. Raised arches showed better performance against settlement, but were more vulnerable in seismic conditions. In contrast, dro‎p arches, due to the more uniform distribution of stress an‎d reduction of force concentration, had better seismic performance. Increasing the span an‎d the length-to-span ratio led to an increase in stress concentration an‎d the spread of permanent deformations. This study investigated the influence of opening geometry an‎d dimensions on arch structural behaviour during support settlement an‎d seismic activity. Seismic analyses indicated that increasing opening height an‎d width increases structural damage. However, results showed a negligible effect of changing opening dimensions on structural behavior during support settlement.

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