Earthquake Engineering Research Articles

Unique Aspects of Scaffolding Design for the Urgent Seismic Retrofitting of Zagreb Cathedral

The 2020 Zagreb earthquake caused extensive damage to historically significant buildings, including the Cathedral of the Assumption of Mary, a key monument of Croatian cultural heritage. The earthquake rendered the cathedral unsafe due to significant damage to its towers and numerous cracks in its vaults and walls. Urgent measures were necessary to ensure safety and facilitate planned reconstruction and strengthening efforts. A specialised scaffolding design was developed to support inaccessible and unstable areas, involving over 1000 tonnes of steel. This paper details the structural concepts and specific scaffolding design implemented for the urgent restoration and seismic retrofitting of Zagreb Cathedral, ensuring it meets high earthquake resistance requirements.

Advancing earthquake resistance: Hybrid retrofitting of RC frames with FRP and TDS

Traditional and technological retrofitting methods have been proposed over time to enhance earthquake resistance in structures. Friction-type dampers have attracted considerable interest from both researchers and the construction industry because of their versatility in retrofitting, quick installation, and non-destructive characteristics. Moreover, the integration of damping systems with various retrofitting elements and the resulting impact of these hybrid systems on building performance have consistently been subjects of interest. This study involved the construction of three identical half-scale reinforced concrete (R.C) frames. One frame served as the reference (REF), the second was wrapped with Fiber Reinforced Polymers (FRP) material (REF-FRP), and the third was retrofitted using both FRP wrapping and the developed Technological Damper System (TDS-FRP). Quasi-static cyclic experiments were performed on the three structural frames, providing force-displacement and force-rotation relationships. The acquired data were then used to assess the damage states of the frames according to the Turkish Building Earthquake Code (TBEC 2018), and energy consumption rates were determined. Moreover, Finite Element Method (FEM) analyses were performed on REF, REF-FRP, and TDS FRP frames to derive force-displacement relationships, which were subsequently compared with experimental findings. The experiment results indicate that the horizontal load-carrying capacity of the TDS-FRP frame increased by 76 % to 122 % compared to the REF frame, while the REF-FRP frame showed a maximum increase of 14 %. Additionally, the cumulative energy consumption capacity of the REF-FRP frame increased by a maximum of 42 % compared to the REF frame, and the TDS-FRP increased between 51 % and 156 %. At a 1 % drift ratio, shear cracks at the beam ends and column-beam intersections of the REF frame were observed to be significantly reduced in the REF-FRP frame and eliminated in the TDS-FRP frame. Additionally, upon reaching a 3 % drift ratio, it was observed that the TDS-FRP frame remained within acceptable limits as per TBEC 2018, whereas the REF and REF-FRP frames exceeded the advanced damage limit. Additionally, it has been observed that the results obtained from FEM analyses coincide with the experimental results. In this context, the TDS-FRP hybrid application can be considered as an effective and alternative solution for the R.C buildings.

Study on the Effect of Burial Depth on Selection of Optimal Intensity Measures for Advanced Fragility Analysis of Horseshoe-Shaped Tunnels in Soft Soil

Seismic intensity measures (IMs) can directly affect the seismic risk assessment and the response characteristics of underground structures, especially when considering the key variable of burial depth. This means that the optimal seismic IMs must be selected to match the underground structure under different buried depth conditions. In the field of seismic engineering design, peak ground acceleration (PGA) is widely recognized as the optimal IM, especially in the seismic design code for aboveground structures. However, for the seismic evaluation of underground structures, the applicability and effectiveness still face certain doubts and discussions. In addition, the adverse effects of earthquakes on tunnels in soft soil are particularly prominent. This study aims to determine the optimal IMs applicable to different burial depths for horseshoe-shaped tunnels in soft soil using a nonlinear dynamic time history analysis method, and based on this, establish the seismic fragility curves that can accurately predict the probability of tunnel damage. The nonlinear finite element analysis model for the soil–tunnel interaction system was established. The effects of different burial depths on damage to horseshoe-shaped tunnels in soft soil were systematically studied. By adopting the incremental dynamic analysis (IDA) method and assessing the correlation, efficiency, practicality, and proficiency of the potential IMs, the optimal IMs were determined. The analysis indicates that PGA emerges as the optimal IM for shallow tunnels, whereas peak ground velocity (PGV) stands as the optimal IM for medium-depth tunnels. Furthermore, for deep tunnels, velocity spectral intensity (VSI) emerges as the optimal IM. Finally, the seismic fragility curves for horseshoe-shaped tunnels in soft soil were built. The proposed fragility curves can provide a quantitative tool for evaluating seismic disaster risk, and are of great significance for improving the overall seismic resistance and disaster resilience of society.

Deep crustal fluids and their relation to cutoff depths of crustal earthquakes in the North Ibaraki area of northeastern Japan inferred from reflected S-waves

Crustal fluids play an essential role in the activity of crustal earthquakes. The north Ibaraki area in northeastern Japan has shown intense crustal seismicity after the 2011 Tohoku-oki earthquake. In this area, it is discussed that crustal fluids are supplied from the deep part of the Earth's crust and contribute to the genesis of these crustal earthquakes. To investigate the distribution of crustal fluids in this area, we focused on reflected S-waves, which are highly sensitive to the presence of crustal fluids. We developed an approach based on the Markov chain Monte Carlo method to precisely and quantitatively estimate the location of the crustal reflector and its geometry. The obtained results showed that the crustal reflector was located at depths of 15–25 km and dipped shallowly to the northwest. The crustal reflector was positioned above the region characterized by low seismic wave velocity and electrical resistivity anomalies in the lower crust, suggesting that the crustal reflector is the uppermost boundary of a fluid-rich zone. The distribution of the fluid-rich zone closely corresponded to the cutoff depths of crustal earthquakes. This fluid-rich zone was likely the source of the fluid that enhanced seismicity in the shallow part of the crust in the target area. In contrast, the fluid-rich zone itself may have suppressed the genesis of crustal earthquakes. We hypothesized that hydrothermal fluids might affect the shallowing of these cutoff depths. If the hydrothermal fluid was contained in the fluid-rich zone, it could induce a shallow brittle-ductile transition by increasing the temperature of the surrounding rocks.

Investigation of RC structure damages after February 6, 2023, Kahramanmaraş earthquake in the Hatay region

From a tectonic perspective, Türkiye is a geographical region known for its high seismic activity, with some of the most active faults in the world. On February 6, 2023, two consecutive earthquakes with magnitudes of Mw 7.7 and Mw 7.6 struck Kahramanmaraş within a remarkably short time span of 9 h. This event stands out as a rare and unprecedented tectonic occurrence in terms of seismicity and tectonic activity over the past 100 years. The impact of these two major earthquakes on the region's reinforced concrete structures was significant, resulting in severe damage and the collapse of numerous buildings. It is of utmost importance to investigate and examine the design flaws and underlying factors that contributed to the damage observed in the reinforced concrete structures affected by these earthquakes. Such research will not only contribute to the improvement of structural design, seismic regulations, and quality control measures during construction but also enhance our understanding of earthquake engineering. In this study, an in-depth field investigation was conducted on reinforced concrete structures in Hatay, one of the regions most affected by the Kahramanmaraş earthquakes. The damages occurring in the buildings were documented through a detailed field survey and analyzed. A total of 540 reinforced concrete structures in the Hatay region were extensively examined, and the damages that occurred in these structures were photographed and interpreted to understand their underlying causes. Subsequently, based on the findings from the field investigation, a structural model was designed that incorporated the most significant design and construction errors responsible for the damages observed in the 540 examined structures. The devised model was subjected to static push-over analysis and nonlinear dynamic analysis using the SAP2000 finite element software, and the results obtained were interpreted.

A Review paper Advancements in Shear Wall Design for Seismic Resistance in Residential Buildings: A Comprehensive Review

This comprehensive review synthesizes diverse studies, providing valuable insights into the advancements, challenges, and future directions in shear wall design for seismic resistance in multi-story residential buildings. It serves as a reference for researchers, engineers, and practitioners seeking a deeper understanding of shear wall dynamics in the context of structural stability and seismic resilience. Shear walls are a prevalent feature in multi-story constructions as they effectively counteract horizontal forces and offer substantial rigidity and durability within the same plane. This unique quality allows them to carry both significant horizontal loads and provide support for vertical or gravitational loads, thereby presenting a valuable asset in the realm of structural engineering applications. The location and arrangement of shear walls in a building are important factors in their effectiveness in resisting seismic loads. Studies have shown that shear walls arranged in the form of a core at the center of the building are the most effective in reducing top-story displacement during earthquakes. Corrugated steel plate shear walls (CPSW) have been introduced as an alternative to flat steel plate shear walls (FPSW) due to their advantages in terms of stiffness, strength, and ductility. Double layer corrugated steel plate shear walls (DCPSW) have been found to have the highest inelastic deformations, which can be considered an advantage over CPSWs. End shear walls in tall buildings have been shown to decrease maximum inter-story drift and improve seismic performance. Keywords: Shear walls, multi-story residential buildings, lateral support, seismic performance, structural integrity, retrofitting, literature review

Geophysical and numerical approaches to solving the mechanisms of landslides triggered by earthquakes: A case study of Kahramanmaraş (6 February, 2023)

Many landslides occurred in the 11 Turkish provinces affected by the earthquakes centered in Kahramanmaraş in February 2023, and many people lost their lives due to those landslides. To reduce the risks and hazards brought on by landslides induced by earthquakes, it is essential to identify the mechanisms causing landslides to arise in such situations. In this study, the geological strength index and both seismic refraction tomography and electrical resistivity tomography (ERT) geophysical methods were used to determine the failure mechanism of layered sedimentary units defined as flysch (claystone-siltstone-sandstone-marl). The shear strength reduction finite element method (SSR-FEM) was used with the RS2 computer program for model solutions. One of the geophysical methods, ERT, facilitated an interpretation of the cyclic failure mechanism that occurs in flysch, and it was found to be congruent with numerical models. Landslide slip circle depth, water-saturated layers, and resistivity values were determined with the ERT method. Seismic methods were employed to determine the velocity values (Vp, Vs) of the landslip mass. These velocity data, along with the elasticity modulus and Poisson ratios derived from them, were utilized in our numerical model. In the maximum shear strength and horizontal displacement analyses performed on the section line determined before the landslide, the natural state and the situation under the influence of groundwater were examined and the strength reduction factor (SRF) was determined as 1.35 and 1.24, respectively. In an evaluation conducted under the influence of the maximum horizontal ground acceleration (0.22 g) determined by taking into account the seismicity of the study area, it was concluded that instability occurred in the flysches and the SRF value was 0.72. An important finding of this study is that the results of geophysical methods used to determine the lithological properties of sedimentary rock masses and understand the causes of landslides align closely with those of numerical analysis methods, providing high accuracy. These methods also support new approaches, particularly in identifying landslip boundaries and detecting areas with high water saturation. It has been discovered that earthquakes actively contribute to the instability of these kinds of soils.

Optimal intensity measure for seismic performance assessment of shield tunnels in liquefiable and non-liquefiable soils

Relating the ground motion intensity measure (IM) and the structural engineering demand parameter is a crucial step in the performance-based earthquake engineering framework. This study investigates the selection of IM for development of probabilistic seismic demand model of urban shield tunnels subjected to earthquake ground motions in liquefiable and non-liquefiable soils. Nonlinear dynamic effective stress analyses are conducted to develop a database of the intensity measures and structural seismic responses exposed to ground shaking and soil liquefaction. Two advanced soil constitutive models (i.e., Pressure DependMultiYield03 and PressureIndependMultiYield for liquefiable and non-liquefiable soils, respectively) are employed to capture the nonlinear behavior. A suite of 23ground motion intensity measures is selected and assessed based on the evaluation criteria of correlation, efficiency, practicality and proficiency. Eventually, the multi-level fuzzy comprehensive evaluation method is employed to comprehensively consider the four evaluation criteria and establish the optimal ground motion IM suitable for probabilistic seismic demand analysis of shield tunnel structures. The obtained results show that the sustained maximum acceleration is the optimal IM for evaluating the structural seismic response, followed by the peak ground acceleration in both liquefiable and non-liquefiable soils. Peak pseudo velocity spectrum, displacement square integral and Housner spectral intensity are found to be not suitable for the probabilistic seismic demand analysis of shield tunnel structures.

Probabilistic analysis of elevated steel silos for seismic resistance

Probabilistic analysis of elevated steel silos for seismic resistance

Optimized data representation and understanding method for the intelligent design of shear wall structures

The generative intelligent design of building structures has been a rapidly evolving field in recent years, with shear wall structures efficiently designed using generative adversarial networks (GANs). Nevertheless, using RGB images to represent structural design drawings may not accurately capture the correlations and distinctions between building components, leading to shear-wall structure design inaccuracies. To address these challenges, this study proposes an optimized data representation and understanding method for the intelligent design of shear wall structures. Specifically, a component-based feature space data representation method was introduced to achieve a more accurate description of drawing features. A feature mask was also employed to precisely locate the key target areas for generating shear walls, enhancing the model's understanding of the data features. Additionally, a GAN with global and local discriminators was established to enhance the neural network's ability to generate shear wall designs at both the global image and local component levels. Finally, a training method for a GAN with dual discriminators based on feature masks is proposed. Experimental analyses and case studies showed that, compared with existing widely used GAN-based designs, the structural designs generated by the GAN trained with the proposed data representation and understanding methods demonstrated superior consistency with engineer-designed structures and outperformed structural seismic resistance.

Visco-Hyperelastic Constitutive Modeling for High-Damping Rubber Materials During Combined Quasi-Static Compression–Cyclic Shear Deformation Process

High-damping rubber materials utilized in high-damping rubber isolation bearings are frequently subjected to multiple deformations during the occurrence of earthquakes. Typically, large combined compression–shear deformations of the material could potentially cause compressive shear damage to rubber bearings. During this process, visco-hyperelastic properties of rubber materials will greatly change, which would significantly impact the seismic performance of rubber bearings. Thus, to give out a deep insight into their variations, it is necessary and urgent to develop a high-performance numerical method to investigate this process. This paper proposed a visco-hyperelastic constitutive modeling approach for high-damping rubber materials based on the experimental assessment of combined quasi-static compression–cyclic shear deformation process. Within the thermodynamic framework, the Clausius–Duhem inequality associated with the intrinsic dissipation of the material was firstly derived in accordance with the Lagrangian formulism. Then, stress–strain relations were obtained upon considering the occurrence of entropy production due to viscous dissipation. In the model, Stumpf–Marczak strain energy density function, which satisfies the Baker–Ericksen (B–E) inequality, was harnessed to describe the hyperelasticity of the material. By introducing higher orders of strain and strain rates and taking their couplings into account, a generalized viscous dissipation potential was proposed to capture nonlinear strain and strain rate-sensitivity effects of the material. To identify constitutive parameters, the deformation gradient was particularized for the combined quasi-static compression–cyclic shear deformation process. And, an inverse identification procedure was carried out at different levels of compression stress. The prediction results revealed that the proposed model exhibits remarkable prediction ability and adaptivity for different rubber materials during this process. Several new insights were highlighted on the variations of visco-hyperelastic characteristics of high-damping rubber materials with respect to the compression stress. The accuracy of the model was further validated by design parameters including initial shear modulus, secant shear modulus and equivalent viscous damping factor. This work could provide a fundamental guideline for the optimization and reliability analysis of high-damping rubber isolation bearings used in the field of seismic engineering.

Optimizing Retrofit Strategies for RC Frames through Combined Techniques

Over the past twenty years, researchers have directed their efforts towards enhancing the earthquake resistance ofconcrete frames through repair and retrofitting. Two main approaches have emerged for bolstering the seismicresilience of previously intact structures prior to earthquake exposure. The first involves augmenting the existingstructure with additional components like steel bracing, while the second entails reinforcing specific structuralelements, such as employing steel cages. Seismic response analyses have been conducted on multi-story reinforcedconcrete (RC) frames originally designed without seismic considerations. This study aims to assess the effectiveness ofretrofitting techniques by comparing the outcomes of employing steel braces, steel cages, and their combinations. Theseismic performance is evaluated according to the RPA 2003 seismic code for Algeria, following the latest guidelines.Static nonlinear analysis was utilized to compare the seismic responses of existing non-ductile RC frames under variousretrofitting schemes.

Computational and Experimental Substantiation of Strengthening Reinforced Concrete Structures with Composite Materials of Power Plants under Seismic Action

In Russia, a significant number of power facilities built in the 1960s and 1970s are located in regions where seismic effects were revised upward. This has led to an increase in the seismicity of the sites of facilities’ locations by magnitude 1–2 (MSK-64) in comparison with the data of design documentation. During the long-term operating period of power facilities, the load-bearing capacity of building structures, as a rule, decreases. This article presents the results of computational and experimental studies of reinforced concrete structures of thermal power plants and hydroelectric power plants for seismic effects in the range of magnitude 4–10 (MSK-64). The computational studies were carried out using ANSYS 16.0 software, and experimental studies were carried out on stands modeling seismic impacts with the help of hydraulic cylinders. The results of the studies showed that cracking of reinforced concrete structures without strengthening occurs at magnitude 6.0 (MSK-64) of seismic impact, and destruction occurs at magnitude 7.5. Thus, the seismic resistance of structures without reinforcement does not meet the requirements for seismic resistance, and strengthening is required. This study considers a variant of strengthening based on external composite reinforcement with CFRP. It is shown that the strengthening of structures with composite material increases their earthquake resistance up to magnitude 9–10 (MSK-64). This article presents recommendations on the CFRP strengthening of building structures of power facilities, both after receiving damage under seismic impact and in a planned manner to increase seismic resistance. The novelty of this work lies in the fact that quantitative results of increasing the seismic resistance of structures depending on the placement and number of layers of composite material are given.

Identifying the effect of low-cycle fatigue of reinforced concrete structures on the properties of the reducing coefficient under the action of a seismic type load

The object of consideration is seismic design, and the subject of the study is the determination of the reduction coefficient. One of the important problems of earthquake-resistant design is to determine the effect of low-cycle fatigue of reinforced concrete on the reduction coefficient and determine its optimal value. This problem is not disclosed and is not specifically taken into account in the standards for earthquake engineering when determining the maximum bearing capacity of types of structures due to the lack of study of the issue. To solve the problem, a series of experimental studies were carried out on low-cycle fatigue of reinforced concrete bending elements and frame units. The range of results of the reduction coefficient values and the degree of influence of monocyclic fatigue on the properties of the reduction coefficient are obtained. A feature and characteristic of the results obtained is that the reduction coefficient Rμ depends on the nature of the hysteresis deformation pattern and the plastic life of structural elements estimated by the plasticity coefficient μ, which is significantly influenced by low-cycle fatigue manifested at peak accelerations of strong seismic impacts. The above test algorithm, the feature and characteristics of the results obtained made it possible to solve the problem under study. The results obtained are accepted for practical use in the action of seismic loads: on the calculation of strength taking into account new low-cycle coefficients, reduction coefficients for determining the spectra of design reactions and seismic loads, taking into account energy absorption. New reduction coefficients are proposed for determining the spectra of calculated reactions and seismic loads

Reevaluating soil amplification using multi-spectral HVSR technique in La Chana Neighborhood, Granada, Spain

This work presents a thorough reevaluation of soil amplification in the La Chana neighborhood of Granada through a pioneering application of the horizontal-to-vertical spectral ratio technique on seismic noise data using various spectral approaches. The research recycles old seismic noise data recorded at 34 stations with 2 Hz instruments in the year 2010, supplemented with additional measurements recorded with broadband seismometers at nearby locations in the years 2013 and 2017. Initial traditional processing identifies a narrowband dominant frequency around 1.5 Hz, attributed to artificial or anthropogenic sources. To address this, the Maximum Entropy Algorithm was implemented to smooth the spectral response below 1 Hz, and filter out frequency peaks with very narrow spectral bands, while preserving the narrowband frequency around 1.5 Hz in some records. The Thomson Multitaper method further refined the spectral ratio, emphasizing the detection and suppression of narrow frequency bands that may be related to industrial activity. The results demonstrated the reappearance of the 1.5 Hz frequency, but this time without narrow bandwidths, indicating its possible correlation with the natural ground movement. Fundamental periods, ranging from 0.45 s to 0.88 s, suggest a diverse lithological composition, indicating the presence of layers of sands, clays, conglomerates, and carbonates over a basement that represents the main impedance contrast in the area. The multispectral approach surpasses conventional methods in precision and reliability, providing valuable insights for earthquake risk assessment, urban planning, and engineering decisions in seismically active regions.

Comparative sustainability and seismic performance analysis of reinforced conventional concrete and UHPC bridge piers

Ultra-high performance concrete (UHPC) boasts excellent mechanical properties, but it comes at a high cost and has a significant environmental impact. This study conducts a comprehensive life-cycle analysis (LCA) on reinforced concrete bridge piers to investigate the environmental implications of integrating conventional concrete (CC) and UHPC in seismic design. The analysis covers both materials and members. At the material level, the global warming potential (GWP) from UHPC manufacturing is calculated using a comprehensive database that includes UHPC mixture details, fiber quantity, geometry, mixing and curing processes, loading age, and compressive strength. At the member level, seismic performance is assessed through capacity-to-demand ratios of strength and ductility. A total of 1280 CC and 2240 UHPC bridge piers are virtually tested with comparable functional unit values, and their GWPs are calculated. The study reveals a proportional relationship between GWP per m3 of UHPC manufacturing and its compressive strength. The GWP of CC and UHPC piers designed using the strength-based approach increases with the capacity-to-demand ratio. When the capacity-to-demand ratio is relatively large, the GWP exhibits rapid nonlinear growth. Adding more reinforcement to achieve a higher capacity-to-demand ratio is inefficient. Moreover, both CC and UHPC piers designed using the ductility-based approach show no strong correlation between GWP and the capacity-to-demand ratio. Surprisingly, using a higher grade of UHPC does not improve seismic resistance; instead, it leads to increased GWP. Effective strategies, such as reducing cross-sectional area and increasing the reinforcement ratio, prove beneficial in enhancing material efficiency and reducing GWP. Additionally, the utilization of a specific pipe section enhances material efficiency, improves seismic resistance, and results in lower GWP.

Development and experimental validation of a novel double-stage yield steel slit damper-buckling restrained brace

This research is focused on the development and experimental validation of a novel double-stage yield steel slit damper-buckling restrained brace (SSD-DYB) system designed for seismic resistance of steel structures. The SSD-DYB integrates the energy dissipation capability of a steel slit damper (SSD) in its initial segment, enhancing performance in the case of lower seismic intensities levels while employing a larger segment for higher load resistance to maintain structural stability. The results of the study show that the proposed SSD-DYB is capable to reduce the weight of similar all-steel buckling restrained braces (BRBs) successfully addressing critical points through stiffeners and top and bottom plates. Additionally, the U-shaped element exhibits resilience during seismic loads, indicating its potential for replacing cores without failure which would be beneficial for seismic retrofitting of buildings. Experimental tests show that varying the number and shape of SSD strips significantly impacts the hysteresis curve's maximum load and dissipated energy (i.e., adding strips increased energy dissipation by 33.48 % for SSD-DYB-1), which can be used to control the proposed device for a specific performance target. Stopper mechanisms within the SSD-DYB regulate load distribution between segments and can be used to control the device and its transmitting capacities. Finally, an optimized SSD-DYB has been proposed with promising performance to be used by researchers for designing new structures or retrofit old ones.

Effect of the Kahramanmaraş earthquake on standing water tanks in the Adana region and buildings in Hatay-Antakya

It is known that the devastating earthquakes experienced in Türkiye in recent years have caused significant loss of life and structural damage throughout the country. Especially the large-scale earthquakes that occurred in Kahramanmaraş on February 6, 2023 and the effects of these earthquakes are examined in detail by researchers. In post-earthquake inspections, it is emphasized that structures such as hospitals and water tanks that need to provide emergency services after the earthquake should be examined in detail and that these structures should be earthquake resistant. In this study, while material-related damages in the structures in the regions affected by the Kahramanmaraş earthquake are examined, the importance of structural improvements, especially in order to increase the earthquake resistance of water tanks, is emphasized. It was also stated that the reasons for the building collapses that occurred after the earthquake in Hatay were discussed in detail. This study makes a valuable contribution to increasing the durability of structures in earthquake risk areas.

Plastic hinge length in reinforced HPFRCC beams and columns

The use of ductile concrete materials such as High Performance Fiber Reinforced Cementitious Composites (HPFRCCs) within plastic hinge regions of structural components has garnered research interest in order to improve the seismic resistance of reinforced concrete structures. While experimental and numerical results appear promising in reducing component damage and probability of system level collapse, accurate nonlinear analysis tools capable of capturing the influence of axial load well into a component’s inelastic regime is needed. In this study, a series of 180 high fidelity numerical simulations of HPFRCC beam–column elements are simulated and used to calibrate new plastic hinge length expressions for concentrated and distributed plasticity models for use in system level structural analysis. The numerical models cover a range of HPFRCC material properties, reinforcement ratios, shear span lengths, and axial load levels. The ability of the newly developed expressions to predict component inelastic rotations are subsequently compared to hinge length expressions in the literature and the inelastic rotations of 47 experimental components. The results of this study provide new insights into the effects of axial load on the plastic hinge behavior of HPFRCC components, significantly improves on the accuracy of past plastic hinge length expressions allowing for more accurate modeling of HPFRCC component responses and system level behavior.

Structural Analysis of Unreinforced Masonary and Reinforced Masonary Structu

This paper presents a comprehensive investigation of the structural analysis of unreinforced masonry (URM) and reinforced masonry (RM) structures, tracing the evolution from traditional construction techniques to modern engineering practices. Historically, the focus of structural design in ancient buildings was largely on geometry and material form. With the advent of steel and concrete, this focus shifted to the strength and resilience of materials. Utilizing both experimental data and computational modeling, this study compares the structural performance of URM and RM, highlighting the strengths and weaknesses of each method. The findings indicate that reinforced masonry structures exhibit superior strength and stability, making them more suitable for seismic regions, while unreinforced masonry can still be viable under specific conditions. The study concludes with recommendations for integrating traditional construction techniques with modern materials to enhance building safety and resilience.