Structural Performance Levels Research Articles

Research on out-of-plane vibration band gap calculation of two-dimensional periodic grillage structures based on spectral element method

The vibration of ship and marine structures directly impacts their structural performance and noise levels. Therefore, the vibration band gap characteristics of two-dimensional periodic grillage structures are investigated based on spectral element method in this article. Firstly, the governing motion equation of out-of-plane vibration of periodic grid structures is established in light of the Bloch theorem, and the shear spring oscillator system is introduced to simulate the first-order vertical shear vibration of bottom plate. As a result, the periodic oscillator coupling grid structure model can be proposed. Based on the periodic grid structures, the influence of material distribution on vibration band gap is obtained. Meanwhile, the dispersion relations and vibration transmission of periodic coupling model are calculated and the coupling effect of local resonance system on the band gap characteristics is analyzed. At last, a general approach for equating periodic grillage unit to numerical model is outlined and summarized on basis of the similarity of dynamic properties. The effectiveness and accuracy of the numerical method in out-of-plane vibration band gap analysis of periodic grillage structures are validated through the computation and model test.

Seismic Upgradation of Building Using Shear Wall and Bracing

Abstract: The seismic assessment prepare comprises of exploring in case the structure meets the defined target structural performance levels. The main goal during earthquakes is to assure to people is minimized and beyond that to satisfy postearthquake performance level for defined range of seismic hazards. Rehabilitation prepares points to progress seismic execution and adjust the lacks by increasing quality, firmness or distortion capacity and making strides associations. Hence, a proposed retrofit execution can be said to be fruitful in the event that it comes about an increment in strength and ductility capacity of the structure which is more noteworthy than the requests forced by earthquakes. Seismic force, predominantly being an inertia force depends on the mass of the structure. As the mass of the structure increases the seismic forces also increase causing the requirement of even heavier sections to counter that heavy forces. And these heavy sections further increase the mass of the structure leading to even heavier seismic forces. Structural designers are met with huge challenge to balance these contradictory physical phenomena to make the structure safe. The structure no more can afford to be rigid. This introduces the concept of ductility. The structures are made ductile, allowing it yield in order to dissipate the seismic forces. A framed structure can be easily made ductile by properly detailing of the reinforcement. But again, as the building height goes beyond a certain limit, these framed structure sections (columns) get larger and larger to the extent that they are no more practically feasible in a structure. There comes the role of shear walls. Shear walls provide ample amount of stiffness to the building frame resisting loads through in plane bending. But they inherently make the structure stiffer. So, there must be a balance between the amount of shear walls and frame elements present in a structure for safe and economic design of high-rise structures

Investigation of seismic resistant structures with various moment-resisting frame systems and pushover analysis

Earthquakes are a serious threat in the construction of multi-storey buildings in Indonesia, which are divided into several seismic design categories. The design of seismic-resistant buildings requires the management of plastic hinges to reduce seismic loads. The aspects of seismic-resistant structural design in Indonesia are regulated by SNI 1726:2019, SNI 1727:2020, and SNI 2847:2019. Intermediate Moment Resisting Frame System (IMRFS) and Special Moment Resisting Frame System (SMRFS) are used based on seismic category and earthquake intensity. Pushover analysis is used to analyze the structures behavior when exposed to seismic loads. This research designs seismic resistant structures with IMRFS and SMRFS at different locations with the aim of assessing structural performance and gaining reinforcement to the concrete ratio, which is relevant for the design and construction of multi-storey buildings in Indonesia. The results of this research are the structural performance levels, reinforcement volume, concrete volume, and the reinforcement to concrete volume ratio. Both IMRFS and SMRFS reached Immediate Occupancy to Life Safe performance levels after the earthquake because their monitored displacement was not significantly different. The structural failure modes of both systems meet the Strong Column–Weak Beam requirements. The distribution of plastic hinges also remains in the Immediate Occupancy category.

Seismic evaluation and retrofit of a typical reinforced concrete hospital building in Indonesia with DCFP isolation system

In this paper, a study on seismic evaluation and retrofit of a typical reinforced concrete (RC) hospital building in Indonesia is presented. Seismic evaluation is performed against basic structural performance objectives outlined in the current code for structural seismic evaluation. The target building is a typical 5-story RC building designed by the 1970s Indonesia seismic and building codes, which imposed lower seismic demand and were not as strict as the current codes in the requirements for strength and ductility. The first part of the paper describes a seismic evaluation procedure against specific target performance levels. Nonlinear time history analysis (NLTHA) is conducted and structural performances were evaluated against structural responses (base shear force and inter-story drift ratio) and acceptance of seismic performance level for local (element rotational limit) and global (roof drift ratio) performance criteria under 225, 975, and 2475-year return period earthquake scenarios. Results reveal that seismic performances of some structural elements are unsatisfactory and under the acceptable performance level, especially for 2475-year return period (BSE-2 N/MCER) earthquake scenario. Seismic retrofit is thus recommended and the use of double-concave friction pendulum (DCFP) base-isolation system as a retrofit strategy is explored. The seismic performance of DCFP-retrofitted building is examined by NLTHA, where effectiveness of DCFP base-isolation system in improving seismic performance is confirmed by comparing structural responses, local and global structural performance of the existing building and the DCFP-retrofitted building under 2475-year return period earthquake scenario. Results of NLTHA demonstrate that local structural performance level has improved from Collapse Prevention to Immediate Occupancy level, whereas the global structural performance has improved from Limited Safety level to Operational level.

Seismic Performance Assessment of Conventional Construction and Ductile Concrete Moment Frames Using Performance-Based Unified Procedure

A Performance-Based Unified (PBU) procedure has recently been proposed by the National Research Council Canada (NRC) to systematically evaluate seismic design requirements available in the National Building Codes (NBC) of Canada. Conventional Construction reinforced Concrete Moment-resisting Frame (CC-CMF) and Ductile reinforced Concrete Moment-Resisting Frame (D-CMF) systems were used in this paper to first assess the proposed PBU procedure and second determine the adequacy of the basis for seismic design requirements in NBC and see its performance margin against different structural performance levels. Results indicate that the detailed screening in the PBU procedure efficiently reduces the number of Incremental Dynamic Analyses (IDA) by more than 60% for CC-CMF while providing remarkable accuracy. It was also found that the CC-CMF system designed for the Normal importance category can provide an adequate margin against Life Safety (LS) performance level objectives, while the D-CMF system designed for the same importance category passes the Collapse Prevention (CP) performance level criteria.

Evaluation and Strengthening Recommendations of Rectorate Building Muhammadiyah University of Sumatra Barat Due to Earthquake

The UM Sumbar Rectorate building suffered structural damage after 33 years. During service life, earthquakes have frequently occurred, the largest was 7.6 magnitude earthquake 2009 in Padang. The structural components have never been handled. This study aims to identify the existing condition as a basis for handling structural damage. Research activities are structure inspection, structural analysis, and determining structural improvements. The building has been deflected by 1° (± 10cm). The majority of structural elements are cracked due to overcapacity. Based on ATC 40 pushover analysis results, it found that 10 steps on x-direction and 11 steps on y-direction of push loads on the structure until it collapsed. Structure performance level is Life Safety, which is in a plastic condition. Strengthening are suggested to increasing column, building ductility, and implementing a dilation system. Evaluation the foundation structure and soil investigation are necessary before planning the strengthening.

Improving the lateral load resistance capacity of cellular lightweight concrete (CLC) block masonry walls through ferrocement overlay

Cellular lightweight concrete (CLC) block masonry is an eco-friendly building material gaining popularity in both developed and developing countries. Despite its increasing use, the material's behavior under seismic loading remains insufficiently understood. This research involved quasi-static testing of two full-scale CLC blocks masonry walls strengthened with ferrocement overlay. One of the strengthened walls was subjected to confinement, while the other was unconfined. The aim was to assess their seismic performance by comparing force deformation curves, damping, stiffness degradation, and structural performance levels with non-strengthened walls. The findings indicate that the strengthened masonry outperformed the unreinforced version, suggesting that CLC block masonry exhibits potential for effective performance in low to moderate seismic zones.

The Influence of Base Isolator on The Reinforced Concrete Structures at Sapadia Mataram Hotel Earthquake-Induced

Ring of Fire and at the intersection of three tectonic plates. Efforts are needed to minimize earthquake damage, one of which is the use of a base isolator system. This study aims to determine the effect of using High Damping Rubber Bearing (HDRB) with a diameter of 800 mm on the behavior of reinforced concrete structures in tall buildings under seismic loads. The research location is the 7-story Sapadia Hotel building in the city of Mataram. The research is conducted by analyzing a 3D model of the fixed base structure and the base isolator structure using numerical analysis. The results show an increase in the base displacement of the base isolator structure by 59% in the x-direction and 44% in the y-direction, while the inter-story displacement decreases by 36% in the x-direction and 69% in the y-direction. The use of base isolators can reduce the shear force by 35% in the x-direction and 15% in the y-direction. Based on the pushover analysis, the roof displacement values for the fixed base and base isolator structures are 0.159 m and 0.129 m respectively. These values can be used to determine the structural performance level according to ATC-40. The maximum drift value for the fixed base structure is 0.0055 m. For the base isolator structure, the maximum drift value is 0.0044 m, categorized as Immediate Occupancy (IO). This value can be used to determine the performance level of the structure based on ATC-40. The maximum drift value of the fixed base structure is 0.0055m. While in the base isolator structure, the maximum drift value is 0.0044 m which is included in Immediate Occupancy (IO). Thus, the use of base isolators in high-level buildings is able to reduce post-earthquake damage and the building is still safe to continue using.

Quantification of structural and non-structural robustness of tall steel buildings using a straightforward methodology

Assessing the robustness of structures accurately provides structural engineers with important information about constructed or designed buildings. The purpose of this research is to evaluate a straightforward methodology proposed by the Multidisciplinary Center for Earthquake Engineering Research (MCEER) for estimating the robustness index of high-rise buildings with different occupancy. Therefore, 24 and 48-story steel structures with a bundled tube system consisting of nine integrated rigid cells at the height of the building are designed based on AISC 360–16. Six occupancies including Residential, Hotel, Commercial, Parking, Office, and Industries are considered for each group of buildings. The behavior of the structures is investigated using incremental dynamic analysis under near-field earthquakes. Also, the development of seismic performance levels of structures is suggested and the fragility curve of buildings in various limit states was obtained through statistical and probabilistic methods. The damage ratio of the structural system and non-structural components, including mechanical and electrical equipment, exterior walls, and partitions, was determined for each structure type, according to HAZUS guidelines. Then, the suffered direct loss on the buildings was estimated at the risk level with an exceedance probability of 10% over 50 years and a return period of 475 years according to the MCEER report. The studied buildings are considered operational for 30 years and 50 years. Finally, the robustness index and quality function of each part of the buildings is calculated. It is observed that the robustness of the elements of a structure is dependent on the role of its structural or non-structural component in serving the building with a specific occupancy. The results indicate that the height and considered lifespan for the structure have a significant effect in calculating the seismic loss function of tall steel buildings. This methodology can be improved by determining performance measures for buildings with different characteristics and defining new damage factors. It is recommended that to verify the seismic design of structures, an acceptable range for the robustness index can be quantified based on the building characteristics and the specification of the site.

Data-based equations for damage evaluation of reinforced concrete columns with square cross sections

This study aims to develop simple equations for assessing the damage of reinforced concrete (RC) columns subjected to seismic loading. A fiber element model in OpenSees, validated against experimental data, was used to generate a large dataset of 56548 data values for various RC columns. The Monte Carlo Hierarchical Adaptive Random Partitioning (MC-HARP) strategy was then applied to evaluate the sufficiency of the dataset and propose reliable equations for estimating the residual displacement ratio (RDR), damage index (DI), and residual curvature of RC columns under given displacement demands. A relationship between these parameters and the structural performance levels was also established. Residual displacement is a practical measure that can be observed in the field after an earthquake. The proposed equations facilitate the determination of the performance level of the structure after an earthquake event. The findings of this paper can also be used in designing new structures within a performance-based seismic design (PBSD) context.

Analisa Level Kinerja Struktur Pada Bangunan 12 Lantai Dengan Metode Pushover

There have been many earthquakes in Indonesia, especially West Sumatra. There was a fairly large earthquake, one of which was in 2009 with a magnitude of 7.6 on the Richter scale centered in Padang Pariaman, causing damage to vulnerable structures and loss of life. Therefore, evaluating the seismic vulnerability of buildings before an earthquake occurs is an important step in preventing damage to buildings and loss of life. In this study, a pushover analysis was carried out to determine the level of structural performance. The method used is a 12-storey building where both the existing building and its detailed properties are known, modeled using the Software Structural Analysis Program (SAP2000) Version 23. From the analysis results, the structure of the 12-storey building will experience the first yield point when given the 3rd pushover load, both at in the X-direction and Y-direction and the building structure will collapse when given the 10th pushover load in the X-direction and the 8th in the Y-direction. The performance level of the 12-story building structure is included in the Damage Control (DO) category level for the X-X direction, which means the transition between Immediate Occupancy (IO) and Life Safety (LS). Meanwhile, in the Y-Y direction, the structure is included in the Immediate Occupancy (IO) category level. Thus, in this case the building is still able to withstand the burden of the earthquake that occurred, the building can also be used again when it has received the earthquake load and the risk of human casualties is relatively small.

Evaluation of Soil Structure Interaction Effects on Seismic Response of RC Framed Buildings Using Simplified Method

In the current practice for the design of the building structure is done by considering the footing as fixed based. The mid-rise buildings having variation in storey height from 3- to 10-storey were selected for the research. In this research, analysis was done to study into the interaction between the seismic response of RC-framed buildings and the soil-structure for various soil types. To study the linear responses of the structures, the model was developed in FEM software SAP2000. The underneath soil was modelled by using direct method, where the soil is considered as solid element. The considered depth of soil was considered 30 m and the viscous spring dashpot were applied to avoid the reflection of seismic waves in soil medium along the effective horizontal soil boundaries. The seismic response variables such as maximum lateral deflection, inter-storey drift and fundamental time periods have been studied. SSI amplified the lateral deflection, inter-storey drift and time period of structure shifting the performance level from life safety to near collapse level. Fundamental time period of the first mode was increased by 23 % for very soft soil. The maximum lateral deflection of 10-storey building for very soft soil was amplified up to 282 % for Kobe and the performance level was shifted from life safety (1.5 %) to collapse level for all the considered model for soil type D . The performance level of structure was checked against the different soil types on varying storey height and finally a simplified method has been proposed to incorporate the effects of SSI in fixed base structures.

Numerical and experimental analysis in seismic performance of post-earthquake reinforced concrete frame retrofitted with ECC

In order to further demonstrate the effectiveness of engineered cementitious composites (ECC) in repairing and strengthening the post-earthquake damaged structure, at the overall structural level, experimental and numerical comparative analysis of structural seismic performance before and after “retrofitted with ECC” is conducted in this paper. A 1:2-scale reinforced concrete frame is tested under cyclic reversed loading and a new ECC material’s constitutive model is proposed in this paper for improving the accuracy and feasibility of numerical modelling. The modelling method and newly proposed constitutive model of ECC has been demonstrated to be workable and accurate. Based on numerical and experimental data, the increase of the average yielding displacement after the installation of ECC is relatively significant (80.4% to 156.4%), and the repairing method using ECC in post-earthquake damaged RC frame can restore and even exceed the original frame’s load bearing capacity. Comparing the ultimate inter-story drift ratio, the ratio with ECC is about 31.0% higher, indicating that ECC has good deformation capacity and the usage of ECC is indeed an effective method to improve deformation capacity in repairing and strengthening post-earthquake damaged structures. The results confirm the effectiveness and superiority of retrofitting ECC in post-earthquake damaged structures for the reason that the repaired structure can reach the same level of seismic performance as the original structure. The “repairable” characteristic can be used in the design of earthquake resilient structures.

Minimization of the stress concentration in Formed Parts through Non-Parametric Optimization

Parametric and non-parametric are the main optimization methods that are used in various industrial fields. In non-parametric optimization, the process of manipulating the node locations (shape optimization) or removing mass without changing the node locations (topology optimization) is adopted to achieve a desired objective. This structural optimization is formulated as a non-parametric problem, and for analysis purposes, ABAQUS/CAE software is adopted for this approach. Manufacturing process like forming is always linked with stress concentration, especially in the sharp ends and variable cross sections like holes and fillets. The problems of representation and finding the optimal and better structural design of some known quantities such as reactions, loads and masses is not easy. A large deflection may be induced in a structure when experiencing severe mechanical loads. In this work, the numerical method has been presented to investigate a method for optimization of formed parts geometry. Numerical examination confirmed that high-stress concentrations are generated in many places. Material distribution is highly influenced by nonlinearity and the new layout will result in intermediate densities. In such cases, the nonlinear elasticity like nonlinear strain must be considered. As a result, the non-parametric optimization can offer good design flexibility to use the existing model with ease of setup and without the need for parameterization. It can provide a conceptual design that can reduce the structure's weight to the maximum extent in the early design stage. This work is going to optimize the design of the formed plates by reducing the volume while maximizing its stiffness. As a recommendation, in order to provide an attractive approach with suitable levels of structural performance, the combination of both optimization methods is the short way to achieve this aim.

Seismic fragility analysis of the steel frame with new layered assembled joints

In order to improve the assembly efficiency of the steel frames, a new fully-bolted core tube joint was proposed in combination with the seismic performance requirements of the joint. Cyclic loading tests were carried out on both new and traditional joints to study their seismic performance, and the joint parameters obtained from the tests were introduced into the overall frame model in SAP2000 to perform Incremental Dynamic Analysis. Based on the single-parameter damage model and the two-parameter damage model, the structural performance level limits were defined, the damage states were classified, and the seismic fragility analysis of the structure was performed. The results showed that the fragility curves of the steel frame with the new joint were enveloped within the fragility curves of the steel frame with the traditional joint under both single and double damage indices, and the collapse resistance reserve factor of the steel frame with new joint was larger. That is, the use of the new joint could reduce the failure probability of the structure under each damage state and improve the collapse resistance of the frame. The median PGA values of the structure based on the single-parameter damage index were smaller than those based on the two-parameter damage index in the LS1 ∼ LS2 limit states, and the opposite was true in the LS3 ∼ LS4 limit states, meaning that the cumulative energy dissipation had an obvious influence on the evaluation of the seismic performance of the structure, and the combination of the two-parameter damage index could better predict the damage degree of the structure. Additionally, increasing the inner sleeve height in the joint domain improved the overall performance and reduced the failure probability of the structure.

Application of Capacity Spectrum Method (CSM) for non-symmetrical reinforced concrete high-rise buildings as a tool for seismic design

The development of earthquake resistance design of structures in the last decade has been critically changing from strength and ductility to performance criteria, where the structure is decided for various levels of structural performance. To understand the structural performance because, at time, a large earthquake load on the structure will experience structural yielding, non-linear analysis with the capacity spectrum method will be performed. The relationship between roof displacement and base shear force is described by a curve that describes the structural capacity is a capacity curve. To determine the behavior of the structures under review for a given earthquake intensity, the capacity curve is then compared with the performance demand based on various earthquake intensities. The results of the case studies for reinforced concrete portals non-symmetrical 3D concluded that the convergence obtained at the point of the structure performance is and . The displacement results for the actual structure () were 286.71 mm and building base shear coefficient was 15.46 %.

Performance-based Analysis of Building Structures in Various Earthquake Zones

The structural design of an eight-story building was examined to determine its performance in resisting ultimate loads. This was necessary for applying the building design in Indonesian regions with low to high seismic hazard levels. Studies have indicated that pushover analysis is suitable to assess the capacity of building structures against earthquake loads. However, as the structural design of each building produces its nominal strength, performance analysis must always be conducted. This study aimed at comparing the structural performance of buildings in regions with low, medium, and high seismic hazards, represented by the cities of Palembang, Jakarta, and Palu, respectively. A performance-based analysis was conducted using the pushover method to obtain the performance points. The responses of the building structures were the base shears, floor drifts, and inter-story drifts. The structural performance levels in the three regions were between immediate occupancy and life safety or were categorized as damage control, indicating minor damage. Because the structures exhibited high stiffness and ductility, they resisted the ultimate forces up to the damage control performance level in all regions. The greatest lateral drifts of 79.744 mm and 51.656 mm in the X- and Y-axis directions, respectively, occurred in Palu’s high seismic hazard region. The lowest lateral drift occurred in Palembang’s low seismic hazard region, in the X- and Y-axis directions of 59.401 mm and 38.378 mm, respectively.

Structural Performance of Buildings with Tension-Only Braced Frame Under Seismic Loading

In accordance with SNI 1726-2019, structures with tension-only braced frames (ToBF) can be used as seismic force-resisting systems for seismic design category (SDC) A to C, with a height of up to 10m. Limited study was done on this subject, hence a numerical study was conducted to better understand the structural performance. The models studied were of regular structures of SDC D, varying in height. The analyses used modal response spectrum analysis (MRSA) for design, and linear response history analysis (LRHA) to evaluate the response. Finally, pushover analyses were conducted to determine the structural performance levels. The study shows that structural design can be done for all models using MRSA, satisfying all requirements. When evaluated using LRHA, results reveal that requirements were not satisfied for structures with heights exceeding 10m. Analysis when reviewed using pushover analysis, results show that the performance levels for all buildings are Immediate Occupancy. However, for models with height exceeding 10m, first yielding occurs at a lower base shear than the design base shear, indicating that the value of R used may not be adequate. Further review reveals that the ToBF can be used as a seismic force-resisting system, with proper design and arrangements.

Performance Evaluation of Structures with Buckling Restrained Braced Frame Under Earthquake Load

Structures with buckling-restrained braced frames (BRBF) resist lateral load, i.e., earthquake, using special bracings that yield under axial tension and compression loads. Following the applicable building code SNI 1726-2019, the design for the BRBF structure has a limitation on the structure height for seismic design category D, which is 48 meters. Three structures are modelled: a 5-story building, a 10-story building, and a 20-story building, to evaluate the height limitation on the code. The initial design of the structures used modal response spectrum analysis (MRSA), then the structures were checked using linear response history analysis (LRHA). Finally, a pushover analysis was conducted to obtain the structural performance level. The study revealed that the structural design for BRBF with MRSA satisfies all requirements of SNI 1726-2019. However, the results of the evaluation of BRBF with LRHA show a structure exceeding the height limit does not meet the requirement for inter-story drift. The pushover analysis showed that the structure’s performance reached the Immediate Occupancy (IO) level. Thus, all structures with BRBF in this study that were designed using MRSA have satisfactory performance under the seismic design load, even though the height limit has been exceeded.

Studi Kinerja Struktur Beton Bertulang Beraturan Yang Didisain Dengan Performance Based Plastic Design

Indonesia is a country that has a very high level of seismicity. It is necessary to plan a building structure that can withstand the earthquake load. Indonesia has adopted guidelines on earthquake resistance planning procedures for buildings and non-buildings. This guideline uses the Performance-Based Seismic Design (PBSD) concept. Performance-Based Plastic Design (PBPD) is a structural analysis with the concept of energy methods which was initially used on steel structures. For reinforced concrete structures this method can also be used using the C2 coefficient. To determine the performance level of structures designed using the Performance-Based Plastic Design method, an analysis of the five-story reinforced concrete structure was carried out. Next, the structure will be analyzed using pushover loads. From the structural performance analysis, the structural ductility value based on Performance-Based Plastic Design (PBPD) was 3.014. The performance level is based on the capacity spectrum at the immediate occupancy level.