Periodic Reporting for period 2 - CIC-BREL (Development of deformation-based method for the behavior of masonry bracing elements, considering the cracked and inelastic state “CIC-BREL” Cracked Inelastic Calculation of BRacing ELements)
Período documentado: 2020-03-16 hasta 2021-03-15
Lateral Force Resisting System, in this case reinforced concrete core walls of a 10 story building consists of gravity columns and shear walls, has been analyzed in linear (assuming linear elastic material behavior of concrete) and nonlinear cracked (considering plastic material behavior of concrete) case, for seismic loading. Starting with the basic method of equivalent lateral force to estimate the seismic loads, then using the up to date method, The Performance Based Seismic Design, which uses real seismic records and apply the accelerations on the building using the software ETABS. After applying the accelerations, maximum resulted forces and deformations have been evaluated. The building then have been designed for the maximum resulted forces.
The contents of the main report are:
-General description of the building, site seismic information, site response spectra, loading and seismic forces including modal response spectrum analysis.
-Linear design of the model for gravity and seismic loads, P-M interaction diagrams developed for U cross section from reinforced concrete, designing longitudinal and shear reinforcement of the shear walls and coupling beam.
-Two variants of Nonlinear model, designing the core wall (shear walls) according to each variant, studying the influence of damping model on the nonlinear dynamic response, as well as the influence of the coupling beam model on the nonlinear dynamic response.
-Design verification, starting with defining the performance objects, and model for time history analysis. Two performance objectives have been studied: Fully operational and Life safety level verifications.
-Additional study was performed for the response of non-structural elements due to seismic loading in two cases: Fully operational and Life safety level verifications.
-Reinforcement Drawings have been finalized and attached to the report.
-Conclusion and recommendations was at the end of the report.
It is important for the society, because the used method could be used for the seismic design of any building. It could be wood building or masonry building. Designing a masonry building case will be the subject of future research project.
Overall objectives: Linear and Nonlinear seismic design of reinforced concrete building using the "performance bases seismic design"
Conclusions of the action: the study and results have been published in a technical report titled" Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method" This repost has the following contents and results:
-The report started with showing the formulae and equations used for elastic calculation of general bracing system, supported with an example in the first Chapter.
-In the second Chapter, the moment-curvature curves, and force displacement curves have been developed for walls with different boundary conditions. At the end of this Chapter explanatory examples for rectangular section and T-section walls with either fixed-pinned or fixed-fixed boundary conditions have been added.
-The matrix formulation for calculating frame structures has been explained and shown in Chapter three. The stiffness matrices for different wall boundary conditions have been developed. The stiffness matrix for both elastic and inelastic material has been shown.
-Flowcharts showing first the classical analytical method to calculate the bracing system have been shown in Chapter four. Then combining the matrix formulation and changed stiffness influence on the calculation has been shown also in a flowchart.
-The shake table test conducted on a reinforced masonry building at the University of California in San Diego in the year 2018 has been shown, with the main features like test setup, forces and displacement results, observations and failure of the building are shown
-in Chapter five, these results will be used to verify the analytical method.
The displacement capacity of a building has been evaluated depending on the displacement capacity of each single wall in the building. This displacement capacity is important in the case of extreme earthquake for life safety and collapse prevention.
The contents of the main report are:
-General description of the building, site seismic information, site response spectra, loading and seismic forces including modal response spectrum analysis.
-Linear design of the model for gravity and seismic loads, P-M interaction diagrams developed for U cross section from reinforced concrete, designing longitudinal and shear reinforcement of the shear walls and coupling beam.
-Two variants of Nonlinear model, designing the core wall (shear walls) according to each variant, studying the influence of damping model on the nonlinear dynamic response, as well as the influence of the coupling beam model on the nonlinear dynamic response.
-Design verification, starting with defining the performance objects, and model for time history analysis. Two performance objectives have been studied: Fully operational and Life safety level verifications.
-Additional study was performed for the response of non-structural elements due to seismic loading in two cases: Fully operational and Life safety level verifications.
-Reinforcement Drawings have been finalized and attached to the report.
-Conclusion and recommendations was at the end of the report.
It is important for the society, because the used method could be used for the seismic design of any building. It could be wood building or masonry building. Designing a masonry building case will be the subject of future research project.
Overall objectives: Linear and Nonlinear seismic design of reinforced concrete building using the "performance bases seismic design"
Conclusions of the action: the study and results have been published in a technical report titled" Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method" This repost has the following contents and results:
-The report started with showing the formulae and equations used for elastic calculation of general bracing system, supported with an example in the first Chapter.
-In the second Chapter, the moment-curvature curves, and force displacement curves have been developed for walls with different boundary conditions. At the end of this Chapter explanatory examples for rectangular section and T-section walls with either fixed-pinned or fixed-fixed boundary conditions have been added.
-The matrix formulation for calculating frame structures has been explained and shown in Chapter three. The stiffness matrices for different wall boundary conditions have been developed. The stiffness matrix for both elastic and inelastic material has been shown.
-Flowcharts showing first the classical analytical method to calculate the bracing system have been shown in Chapter four. Then combining the matrix formulation and changed stiffness influence on the calculation has been shown also in a flowchart.
-The shake table test conducted on a reinforced masonry building at the University of California in San Diego in the year 2018 has been shown, with the main features like test setup, forces and displacement results, observations and failure of the building are shown
-in Chapter five, these results will be used to verify the analytical method.
The displacement capacity of a building has been evaluated depending on the displacement capacity of each single wall in the building. This displacement capacity is important in the case of extreme earthquake for life safety and collapse prevention.
Attending three annual meetings of The Masonry Society.
Paper to the 13 North American Masonry Conference.
Technical Report: Performance Based Seismic Design of Lateral Force Resisting System.
Preparing teaching material (presentations, homework, exams) for structural engineering classes considering seismic design: wood structure, steel structure, reinforced concrete, masonry structures.
Technical Report: Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method.
In the final period, teaching material have been prepared for the classes: "basics of seismic design", "masonry structures, behavior and design".
Paper to the 13 North American Masonry Conference.
Technical Report: Performance Based Seismic Design of Lateral Force Resisting System.
Preparing teaching material (presentations, homework, exams) for structural engineering classes considering seismic design: wood structure, steel structure, reinforced concrete, masonry structures.
Technical Report: Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method.
In the final period, teaching material have been prepared for the classes: "basics of seismic design", "masonry structures, behavior and design".
Performance Based Seismic Design of Masonry Structures:
Current design method of masonry structures, either reinforced or unreinforced, uses the simplified method of equivalent lateral force to
define the forces applied on the structure in case of an earthquake. Dynamic analysis using response spectrum or time history analysis is still
under work.
The current Technical Report: "Performance Based Seismic Design of Lateral Force Resisting System." uses both dynamic methods on
reinforced concrete structure. This could be in a very similar way used on masonry structures. There is very little work done in this field, working
on this subject would give better understanding of the masonry buildings.
Progress beyond the state of the art has been published in a technical report titled" Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method". Redistribution of internal forces in the lateral bracing system considering cracked and inelastic material behavior. Analysis method and verification with shake table test results. Depending on the section geometry, material properties and boundary conditions of the wall, moment-curvature curves and subsequently the force-displacement curves have been drawn. The later has been used the describe the change of the wall stiffness with increased force. This includes, in addition to elastic behavior, inelastic behavior pre and post peak value. The change of the wall stiffness will lead to change of distributed force on each wall, which is different from load distribution in case of considering only elastic wall behavior.
In this study, the lateral capacity and force-displacement of each single wall was an input in a Fortran code, the output was the force-displacement curve of the whole structure as well as its lateral force capacity. This code considers the redistribution of lateral force on each wall due to changed stiffness of the wall with increased load.
Possible future improvement could be to distinguish between shear, flexural and sliding displacement when calculating the single walls or the whole system. Furthermore, current verification has been done on a simple reinforced masonry structure of two T-section walls in one story, verification of a multi-story building of other materials like concrete or unreinforced masonry could also be done in the future.
Current design method of masonry structures, either reinforced or unreinforced, uses the simplified method of equivalent lateral force to
define the forces applied on the structure in case of an earthquake. Dynamic analysis using response spectrum or time history analysis is still
under work.
The current Technical Report: "Performance Based Seismic Design of Lateral Force Resisting System." uses both dynamic methods on
reinforced concrete structure. This could be in a very similar way used on masonry structures. There is very little work done in this field, working
on this subject would give better understanding of the masonry buildings.
Progress beyond the state of the art has been published in a technical report titled" Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method". Redistribution of internal forces in the lateral bracing system considering cracked and inelastic material behavior. Analysis method and verification with shake table test results. Depending on the section geometry, material properties and boundary conditions of the wall, moment-curvature curves and subsequently the force-displacement curves have been drawn. The later has been used the describe the change of the wall stiffness with increased force. This includes, in addition to elastic behavior, inelastic behavior pre and post peak value. The change of the wall stiffness will lead to change of distributed force on each wall, which is different from load distribution in case of considering only elastic wall behavior.
In this study, the lateral capacity and force-displacement of each single wall was an input in a Fortran code, the output was the force-displacement curve of the whole structure as well as its lateral force capacity. This code considers the redistribution of lateral force on each wall due to changed stiffness of the wall with increased load.
Possible future improvement could be to distinguish between shear, flexural and sliding displacement when calculating the single walls or the whole system. Furthermore, current verification has been done on a simple reinforced masonry structure of two T-section walls in one story, verification of a multi-story building of other materials like concrete or unreinforced masonry could also be done in the future.