Numerical Modelling of Underground Water Pipelines exposed to Seismic Loading

The essential factor that must get the interest by the engineers during the primary design stage of underground pipes is understanding mechanism of damage during earthquakes. The attention during design period increased due to the increment of seismic catastrophes throughout the few past decades. Therefore, finite element procedure was used for studying the seismic performance of buried pipes. PLAXIS-2D program was using for simulating the seismic performance of buried pipes using earthquake motion of single frequency. The response of both seismic vertical displacement, and acceleration of the buried pipe were simulated. The experiments of shaking table for two models of buried pipe in dry case that surrounded with sand and gravel were compared with numerical simulation results. According to the obtained results, the amplification of seismic wave raised considerably from the buried pipe base to the pipe crown, the biggest amplification occurred in the highest point of the pipe model. It can be noticed that Plaxis-2D software provides an accurate method for the prediction of seismic behaviour of buried pipe due to the obvious compatibility between the results of experiments and numerical simulation.

Seismic Behaviour of High-rise Frame-core Tube Structures Considering Dynamic Soil-Structure Interaction

As the population grows and land prices rise, high-rise buildings are becoming more and more common and popular in urban cities. Traditional high-rise building design method generally assumes the structure is fixed at the base, because the influence of soil-structure interaction is considered to be beneficial to the response of structures under the earthquake excitation. However, recent earthquakes and studies indicated that SSI may exert detrimental effects on commonly used structural systems. In this study, a numerical soil-structure model is established in Abaqus software to explore the impacts of SSI on high-rise frame-core tube structures. The seismic response of frame-core tube structures with various structural heights, height-width ratios, foundation types and soil types is studied. The numerical simulation results including maximum lateral deflections, foundation rocking, inter-storey drifts and base shears of rigid and flexible base buildings are discussed and compared. The results reveal the lateral displacement and inter-storey drifts of the superstructure can be amplified when SSI is taking into account, while the base shears are not necessarily reduced. Increasing the stiffness of the foundation and the subsoil can generally increase the seismic demand of structures. It has been concluded that it is neither safe nor economical to consider only the beneficial effects of SSI or to ignore them in structural design practice.

Seismic Behaviour of Rc Building Located in Erbil, Iraq and Strengthening by Using Steel Frame Sections Precast Bolt-Connected Steel-Plate Reinforced Concrete

This paper present outside strengthening with precast substructures, is a relatively new retrofitting approach that has recently attracted the attention of researchers. Outside strengthening with precast substructure, in contrast to member-level strengthening technologies (e.g., FRP strengthening, enlarging member section areas, and replacing rebars), is a structure-system reinforcement method that integrates the substructure and the original structure, improves overall seismic performance, and changes the deformation mode of the entire structure. The seismic capability of the exterior strengthening with precast bolt-connected steel-plate reinforced concrete is critically evaluated in this paper (PBSPC) Case studies are used to demonstrate the working principles, numerical methodologies, and design approaches. The simulation results were similar with prior studies, demonstrating that the numerical model was effective. The use of building steel representations reduces construction time, increases efficiency, and lowers costs. The goal of this technology is to lower the seismic displacement demand of nonductile. Current RC structures have steel frames connecting to the building floors. These frameworks run parallel to the structure of the building. Ganjan Life City, a building in Erbil, Iraq, is being used as a case study. The ISC 2017 and ASCE 7-10 earthquake codes were used to evaluate the building’s seismic performance before and after the reinforcement. The analysis’ findings suggest that the recommended technique is correct.