Advance Researches in Civil Engineering
Volume:5 Issue: 2, Spring 2023

A soil exploitation project was introduced and a summary of the obstacles faced in the project was stated. Based on the investigation a compensatory action plan was proposed. The main factors that were considered in developing a compensatory action plan during the revision of the time schedule was discussed. Based on the extensive investigations, tamping quantity was considered as the main determinative factor. The influencing factors was 1) the alteration of the exploitation soil comprising a 50-50 percent of former borrow area and the new borrow area which had the required engineered specifications 2) the proposal of a new pattern for DC. In the compensatory action plan this matter was considered based on the selected pattern by application of total drop quantity to gain a realistic prediction for the schedule plan. 3) As a result of the existence of fine-grained soil in the mix, the time needed for dissipation of excess pore water pressure due to the heavy tamping or heavy seasonal rain between 3 phases and even in each phase alone was considered as a function of tamper quantity. 4) The mobilization of cranes between tamping points linked with tampers quantity based on the DC phases 5) The deficiency of cranes was calculated based on the new compensatory action plan. Since all of these factors’ functionality can be linked to tamping quantity, it was found that this trend is a good way for consideration of parameters that can delay the project and also as a measure for compensatory action plan.

The collision of adjacent buildings with insufficient distance has been observed many times during earthquakes. The main reason for the collision between buildings is usually their out-of-phase vibration, which occurs due to the difference in the dynamic characteristics of the buildings. On the other hand, in the case of tall structures, the phenomenon of pounding between the upper parts of the structure is mostly caused by the effect of wave propagation. Among the issues that have happened in most of the huge earthquakes in the world is the issue of adjacent buildings hitting to each other. This phenomenon occurs due to out-of-phase vibration in buildings that are not far enough apart. Due to the increase in urban population, the vertical development of cities is inevitable. Since most of the large and important cities of the country are located in earthquake-prone areas, it is necessary to give more importance to the issue of buildings hitting each other during an earthquake and reducing its effect in order to reduce the life and financial risks associated with it. In this research, the modeling of adjacent structures and the effect of the impact force on the response of the structures and the examination of the distance of gap are checked. In order to investigate the effect of pounding on the structures, the steel braced frames (3 and 6 stories) are designed and nonlinear dynamic time history analysis is performed for the mentioned models and in case of pounding phenomenon, viscoelastic damper is used to reduce the impact force. The results showed that to apply viscoelastic damper has reduced the displacement significantly.

Rice husk ash (RHA) produced under certain conditions from rice husk as an agricultural surplus material can be used in concrete as a pozzolanic material. Pozzolanic materials improve the durability properties of concrete mainly, but their effects on fresh properties and strength can be different depending on the constituent materials and type of concrete. In this paper, RHA produced from the rice farms of Khouzestan province, Iran has been evaluated for the optimal level of replacement in self-compacting concrete (SCC). To this end, the fresh properties and compressive strength of SCC have been investigated. The used RHA contains 87% silica, mainly in the amorphous state, and has an average specific surface area of 399 m2/kg. The results obtained in this research show that increasing RHA up to 15 % can improve the fresh properties by up to 10%, but it reduces the compressive strength by about 10%. So the 10-15% replacement of cerement with RHA is recommended.

The structural systems used in mid-rise buildings are being developed quantitatively and qualitatively to increase their resistance against gravity and lateral forces. Also, extensive studies are being conducted regarding the introduction and application of new structural systems in mid-rise structures in order to improve the behavior of the structure and reduce the risks caused by the effect of lateral forces. In this regard, in recent years, the use of a structural system with a bracing system has attracted the attention of many engineers and researchers. On the other hand, sometimes due to architectural limitations and the inappropriate location of the building, there is a possibility of torsional irregularity in them, and this issue can be seen in most buildings. X, diagonal and chevron (V, inverted V, combination of V and inverted V and combination of X and diagonal) bracing systems have not been done in mid-rise structures. Therefore, in this study, the investigation and comparison of X bracing system, single diagonal bracing and chevron in mid-rise structures is discussed. In order to achieve the goals of this project, a 10-story structure with a combined system of moment frame and X, diagonal and chevron bracing is modelled in ABAQUS software. The obtained results showed that FM10-V-Ʌ-bracing and FM10-Ʌ-bracing models have the best performance in displacement and base shear, respectively in comparison with a reference model. The higher the stiffness of a structure, the less likely it is to damage and destroy its non-structural components due to less plasticity and displacement; But in case of failure, the destruction will be sudden and severe.

Analyzing and investigating the elastic behavior of frames after buckling is complicated. When a frame is subjected to a force exceeding the critical load, it begins to undergo large deformations. In this case, the theory of small deformations is no longer valid for the structure and the theory of large deformations should be used. Post-buckling analysis of elastic structures always requires solving a set of nonlinear differential equations based on equilibrium equations. The present work deals with the effect of beam-column joint flexibility on the elastic buckling load of plane steel frames and proposes a simplified approach to the evaluation of the critical buckling load of frames with semi-rigid connections according to the assumptions of the Elastica theory. In this study, the equations are simplified using the power series. The elastic buckling load is found to be strongly affected by semi-rigid joints and reveals that the proposed model is computationally very efficient with the expressions presented being general. The paper makes reference to the other researchers in comparing the results.