No abstract

No abstract

In conventional seismic design, the structure is often assumed to be fixed at the base. However, this assumption does not reflect reality. Furthermore, if the structure has close neighbors, the adjacent structures will alter the response of the structure considered. Investigations on soil–structure interaction and structure–soil–structure interaction have been performed mainly using numerical models. The present work addresses the dynamic response of adjacent single-degree-of-freedom models on a laminar box filled with sand. Impulse loads and simulated ground motions were applied. The standalone condition was also studied as a reference case. Models with different fundamental frequencies and slenderness were considered. Results from the impulse tests showed that the top displacement of the models with an adjacent structure was reduced compared with that of the standalone case. Changes in the fundamental frequency of the models due to the presence of an adjacent model were also observed. Results from ground motions showed amplification of the maximum acceleration and the top displacement of the models when both structures have a similar fundamental frequency.

The influence of soil on the dynamic response of soil-structure systems is usually studied on a stand-alone (SA) structure, even though closely adjacent structures form the vast majority of the population, especially in large cities. When structures are closely adjacent to each other, the wavefield in the soil, generated by the vibration of the footings, produces a complex interaction between them. Scant attention, especially by physical experiments, has been paid to this interaction. This work addresses the seismic response of a single degree-of-freedom structure (structure of focus) considering the influence of one and two closely adjacent neighbours. Experiments were performed using a large laminar box filled with sand sitting on a shake table. Results from utilising four recorded ground motions from the 2010-2011 Canterbury earthquake sequence are analysed. The effect of adjacent structures on the acceleration and displacement of the top mass of each structure, as well as the uplift of the footings, are discussed. Changes in the fundamental frequency due to the presence of neighbouring structures are identified. The use of the SA system, without consideration of closely adjacent structures, may result in a significant error in the estimation of the response of the structure of focus. In general, acceleration, lateral displacement and uplift reduced in comparison with that of the corresponding SA case. A footing settlement mechanism, resulting from uplift of the system that reflects the influence of adjacent structures, is also revealed.

No abstract