Seismic assessment of slender high rise buildings with different shear walls configurations

Farghaly, Ahmed Abdelraheem Techno-Press 2016 Advances in computational design Vol.1 No.3

The present study dictates the behavior of shear wall under a seismic event in slender high rise buildings, and studies the effect of height, location and distribution of shear wall in slender high rise building with and without boundary elements induced by the effect of an earthquake. Shear walls are located at the sides of the building, to counter the earthquake forces. This study is carried out in a 12 storeys building using SAP2000 software. The obtained results disclose that the behavior of the structure is definitely affected by the height and location of shear walls in slender high rise building. The stresses are concentrated at the limit between the shear wall region and the upper non shear wall especially for shear walls without columns. Displacements are doubled between the shear wall region and the upper non shear wall especially for shear walls without columns.

Nonlinear analysis of a riverine platform under earthquake and environmental loads

Farghaly, Ahmed Abdelraheem,Kontoni, Denise-Penelope N. Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.6

A realistic FEM structural model is developed to predict the behavior, load transfer, force distribution and performance of a riverine platform under earthquake and environmental loads. The interaction between the transfer plate and the piles supporting the platform is investigated. Transfer plate structures have the ability to redistribute the loads from the superstructure above to piles group below, to provide safe transits of loads to piles group and thus to the soil, without failure of soil or structural elements. The distribution of piles affects the distribution of stress on both soil and platform. A materially nonlinear earthquake response spectrum analysis was performed on this riverine platform subjected to earthquake and environmental loads. A fixed connection between the piles and the platform is better in the design of the piles and the prospect of piles collapse is low while a hinged connection makes the prospect of damage high because of the larger displacements. A fixed connection between the piles and the platform is the most demanding case in the design of the platform slab (transfer plate) because of the high stress values developed.

Seismic analysis of 3-D two adjacent buildings connected by viscous dampers with effect of underneath different soil kinds

Ahmed Abdelraheem Farghaly 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.5

3D two adjacent buildings with different heights founded in different kinds of soil connected with viscous dampers groups, with especial arrangement in plane, were investigated. Soil structure interaction for three different kinds of soil (stiff, medium and soft) were modeled as 3D Winkler model to give the realistic behavior of adjacent buildings connected with viscous dampers under various earthquake excitations taking in the account the effect of different kinds of soil beneath the buildings, using SAP2000n to model the whole system. A range of soil properties and soil damping characteristics are chosen which gives broad picture of connected structures system behavior resulted from the influence soil-structure interaction. Its conclusion that the response of connected structures system founded on soft soil are more critical than those founded on stiff soil. The behavior of connected structures is different from those with fixed base bigger by nearly 20%, and the efficiency of viscous dampers connecting the two adjacent buildings is reduced by nearly 25% less than those founded on stiff soil.

Contribution of Soil-Structure Interaction to Seismic Response of Buildings

Ahmed Abdelraheem Farghaly,Hamdy Hessain Ahmed 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.5

Buildings are susceptible to soil structure interaction effects due to the induced changes in the dynamic characteristics of soil during seismic excitation. Because of this detrimental effect, this paper aims at clarifying the soil structure interaction effect on the seismic response of buildings under strong ground motions to provide damage control and enhance the safety level of such buildings. An iterative dynamic analysis was performed using the SAP2000 program to carry out three dimensional time history analysis of nonlinear soil-foundation-building models under a great earthquake ground motion, and the results show that incorporating the soil structure interaction could have a detrimental effect on the building performance and overestimates the top displacements response. On the contrary flexible bases of buildings have a noticeable effect on the structural behavior of buildings by providing pronounced reduction in the internal forces of superstructure response compared to the fixed base buildings.

Lime addition chemical stabilization of expansive soil at Al-Kawamil city, Sohag region, Egypt

Farghaly, Ahmed Abdelraheem,El-Shater, A.,Naiem, Mostafa Abdou Abdel,Hamdy, Fatma Techno-Press 2020 Advances in computational design Vol.5 No.1

Soil is the fundamental element in the construction process. Soil problems affect the safety of the structures, even so the high quality of the structures and so, bad soil found the structures will affect the lifetime or even destroy the structures built on it. Therefore, the study of soil is an important step in the construction process and the investigation of the most effective characteristics of a special kind of soil (shale soil), i.e. Atterberg limits, swelling pressure, swelling potential and unconfined compression strength, are the most effective soil properties. A big projects will be constructed in new urban extension areas with expansive shale soils, like at Al-Kawamil and new Akhmim shale soils which associated with soil problems, treatment system should be used to ensure the stability of the soil under the structures foundations one of the most effective methods is by adding lime solution to the soil by specific quantities, which affect on the properties of the shale soil by decreasing the swelling and increasing the compressive strength of the treatment soils. Experimenting with the soil added to the lime, it was found that the addition of lime solution 6% improve c j the properties of the soil. The results of the tests showed the high effectiveness of using lime in the treatment of Al-Kawamil soil

Parametric study on equivalent damping ratio of different composite structural building systems

Ahmed Abdelraheem Farghaly 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.14 No.4

Structures consisting of concrete and steel parts, which are irregular in damping ratios are investigated. This investigation is a code-based seismic design of such structures. Several practical difficulties encountered, due to inherent differences in the nature of dynamic response of each part, and the different damping ratios of the two parts. These structures are irregular in damping ratios and have complex modes of vibration so that their analysis cannot be handled with the readily available commercial software. Therefore, this work aims to provide simple yet sufficiently accurate constant values of equivalent damping ratios applied to the whole structure for handling the damping irregularity of such structures. The results show that the equivalent damping ratio changes with the height of the building and the kind of the structural system, but it is constant for all accelerations values. Thus, available software SAP2000 applied for seismic analysis, design and the provisions of existing seismic codes. Finally, evaluation of different kinds of structural system used in this research to find the most energy dissipating one found by finding the best value of quality coefficient.

Train induced dynamic response of a pedestrian tunnel under a four-track surface railway for different soil water contents

Farghaly, Ahmed Abdelraheem,Kontoni, Denise-Penelope N. Techno-Press 2018 Geomechanics & engineering Vol.16 No.4

A reinforced concrete pedestrian tunnel is constructed under a four-track surface railway. Heavy rainfall and soil exposure to drying lead to soil with different water content throughout the year. A railway is an open utility that is subject to rainfall without control on the quantity of the water on it and when there is a tunnel under a railway, the water content of the soil around the tunnel is very influential. This research shows the effects of change of water content in the soil around a pedestrian tunnel under a four-track surface railway. The pedestrian tunnel and the soil block around the tunnel are modeled in 3D by the FEM and are studied under the vibrations induced by the moving trains on the four-track surface railway for different soil water contents and the effects of the soil water content on the dynamic behavior of the tunnel and the surrounding soil are demonstrated.

Parametric Study on Equivalent Damping Ratio of Different Composite Structural Building Systems

Ahmed Abdelraheem Farghaly 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.1

Structures consisting of concrete and steel parts, which are irregular in damping ratios are investigated. This investigationis a code-based seismic design of such structures. Several practical difficulties encountered, due to inherent differences in thenature of dynamic response of each part, and the different damping ratios of the two parts. These structures are irregular indamping ratios and have complex modes of vibration so that their analysis cannot be handled with the readily availablecommercial software. Therefore, this work aims to provide simple yet sufficiently accurate constant values of equivalentdamping ratios applied to the whole structure for handling the damping irregularity of such structures. The results show thatthe equivalent damping ratio changes with the height of the building and the kind of the structural system, but it is constantfor all accelerations values. Thus, available software SAP2000 applied for seismic analysis, design and the provisions ofexisting seismic codes. Finally, evaluation of different kinds of structural system used in this research to find the most energydissipating one found by finding the best value of quality coefficient.

Mitigation of seismic pounding between two L-shape in plan high-rise buildings considering SSI effect

Ahmed Abdelraheem Farghaly,Denise-Penelope N. Kontoni Techno-Press 2023 Coupled systems mechanics Vol.12 No.3

Unsymmetrical high-rise buildings (HRBs) subjected to earthquake represent a difficult challenge to structural engineering, especially taking into consideration the effect of soil-structure interaction (SSI). L-shape in plan HRBs suffer from big straining actions when are subjected to an earthquake (in x- or y-direction, or both x- and y- directions). Additionally, the disastrous effect of seismic pounding may appear between two adjacent unsymmetrical HRBs. For two unsymmetrical L-shape in plan HRBs subjected to earthquake in three different direction cases (x, y, or both), including the SSI effect, different methods are investigated to mitigate the seismic pounding and thus protect these types of structures under the earthquake effect. The most effective technique to mitigate the seismic pounding and help in seismically protecting these adjacent HRBs is found herein to be the use of a combination of pounding tuned mass dampers (PTMDs) all over the height (at the connection points) together with tuned mass dampers (TMDs) on the top of both buildings.

Mitigation of the seismic response of a cable-stayed bridge with soil-structure-interaction effect using tuned mass dampers

Denise-Penelope N. Kontoni,Ahmed Abdelraheem Farghaly 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.6

A cable-stayed bridge (CSB) is one of the most complicated structures, especially when subjected to earthquakes and taking into consideration the effect of soil-structure-interaction (SSI). A CSB of a 500 m mid-span was modeled by the SAP2000 software and was subjected to four different earthquakes. To mitigate the harmful effect of the vibration generated from each earthquake, four mitigation schemes were used and compared with the non-mitigation model to determine the effectiveness of each scheme, when applying on the SSI or fixed CSB models. For earthquake mitigation, tuned mass damper (TMD) systems and spring dampers with different placements were used to help reduce the seismic response of the CBS model. The pylons, the mid-span of the deck and the pylon-deck connections are the best TMDs and spring dampers placements to achieve an effective reduction of the earthquake response on such bridges.