Earthquake-prone Areas Research Articles

Inegol Inscriptions

Roma ve Bizans İmparatorlukları döneminde önemli bir yerleşim alanı durumundaki İnegöl yöresi, Osmanlı Beyliğinin kuruluşuna da ev sahipliği yapmıştır. İnegöl ve çevresi Türklerin eline geçtikten sonra mevcut yapılara yenileri eklenmiş, imar ve inşa faaliyetlerine büyük bir hız ve önem verilmiştir. Ancak yörenin deprem kuşağında yer alması, 1. Dünya Savaşı ve ardından yaşanan Yunan İşgali gibi çeşitli sebepler pek çok yapının tahrip olmasına ya da bütünüyle ortadan kalkmasına neden olmuştur. Bunun yanında ilk inşası Devlet-i Aliyye’nin kuruluş yıllarına uzanan pek çok yapı da çeşitli onarımlarla bazen de bütünüyle yenilenerek günümüze ulaşabilmiştir. Bu çalışmada İnegöl’de Türk döneminde inşa edilen yapılara ait kitabelerin tespitinin ve tanıtımının yapılması amaçlanmıştır. Yapıların kimlik belgesi durumundaki kitabeler üzerinden yapılacak olan bir değerlendirme, yapıların doğru şekilde tarihlendirilmesi, işlevlerinin belirlenmesi, bani (yaptıran) ve usta isimlerinin tespit edilmesi gibi pek çok farklı amaca hizmet edecektir. Çalışmada yörede tespit edilen 15 kitabe ele alınacaktır. Söz konusu kitabeler bütüncül olarak değerlendirildiğinde İnegöl’ün mimari, tarih ve sanat özelliklerinin anlaşılmasına katkı sağlayacak epigrafik bilgilere ulaşabilmek mümkündür. Bu yayında İnegöl yöresinde tespit edilen yapı kitabeleri malzeme-teknik, yazı tipi ve dili, içerik ve süsleme özellikleri gibi farklı açılardan ele alınarak, değerlendirilecektir.

Seismic vulnerability of jacket supported large offshore wind turbine considering multidirectional ground motions

Large numbers of offshore wind turbines in earthquake prone areas increase the scientific interest in analysing their seismic vulnerability. This study investigates the deformation and collapses susceptibility of a 10 MW jacket supported offshore wind turbine (OWT) considering different geometry of pile and jacket. A three-dimensional finite element model of the soil-pile-jacket-tower is developed in ABAQUS. A performance-based analysis is conducted to quantify the engineering demand parameters by choosing first mode spectral acceleration as the intensity measure for different pile length-to-diameter ratios and the base width of the jacket. The significance of considering higher modes and the vertical component of the earthquake motion on the dynamic response of offshore wind turbines is also discussed. Considerable amplification of acceleration is observed at the nacelle due to vertical excitation. In low to moderate earthquake shaking, jacket base width shows a marginal influence on the responses, while a significant impact is observed for strong earthquake shaking. Mudline rotation and acceleration response at the nacelle are the most critical parameters that govern the design under the serviceability limit state. Moreover, it is observed that initiation of the rocking mode of vibration for jacket-supported OWTs resting on a pile foundation is significantly less until its embedment length reduces considerably (3 to 5 m).

Characteristics and Spatial Distribution of Vs30 Based on Microtremor Inversion and MASW Data through Landform Unit in Yogyakarta, Indonesia

The Yogyakarta region is located in the earthquake-prone areas of Indonesia. An earthquake hazard can be assessed by identifying the site conditions from Vs30 to estimate the potential amplification of ground shaking. Site conditions are affected by the earth surface relief and material composition. The landform is characterized by differences in geomorphological structures and processes, relief/topography, and material. This research aims to analyze the characteristics and spatial distribution of Vs30 based on MASW and microtremor inversion for each landform unit in the Yogyakarta region. We collected 545 microtremor and MASW responses from field measurements. Data inversion was performed to obtain a 1D Vs30 model and estimate the Vs30 value. The results are presented in the Vs30 spatial distribution map and site classification. They show that the value of Vs30 is varied in a range of 140 – 1092 m/s. The site classification ranges from SE to SB. The Vs30 value tends to be similar to the USGS model, except in the karst landform in the Gunungkidul area. Here, the site class ranges from SC to SB, while the USGS model ranges from SD to SC. Based on the landform analysis, the higher average values of Vs30 are for karst, followed by structural, denudational, volcanic, fluvial, marine, and aeolian landforms. This difference indicates that local conditions significantly affect the Vs30. The higher the elevation and the steeper the slope, the larger the Vs30 value. Moreover, the higher values of Vs30 are determined by harder and solid/consolidated material.

Local seismic hazard map based on the response spectra of stiff and very dense soils in Bengkulu city, Indonesia

It is well known that seismic hazard assessment should be implemented to design infrastructures in an earthquake-prone area such as Bengkulu. This paper presents local seismic hazard maps based on the response spectra of stiff and very dense soils in Bengkulu city, Indonesia. We collect the soil data and conduct the seismic wave propagation. The input motion for wave propagation analysis is generated from the spectral acceleration curves of stiff and dense soils. Various ground motion parameters such as peak ground acceleration, short-period and long-period spectral accelerations, and amplification factors are presented in microzonation maps. The results show that the peak ground acceleration in the study area ranges from 0.2 to 0.8 g, while the spectral acceleration varies between 0.5–1.5 g and 0.4–0.8 g for periods of 0.2 and 1 s, respectively. The amplification factor of the site is observed to vary from 0.5 to 1.6. Considering other spectral accelerations in Bengkulu, the spectral acceleration design shows a good performance. The results indicate the site characteristics of Bengkulu city, which can provide engineers with site class for structural building design.

Investigation on Rupture Initiation and Propagation of Traffic Tunnel under Seismic Excitation Based on Acoustic Emission Technology.

Traffic tunnels are important engineering structures in transportation, and their stability is critical to traffic safety. In particular, when these tunnels are in an earthquake-prone area, the rupture process under seismic excitation needs to be studied in depth for safer tunnel design. In this paper, based on a construction project on the Nairobi-Malaba railway in East Africa, a laboratory shaking table test with 24 working cases of seismic excitation on a mountain tunnel is designed, and the acoustic emission (AE) technique is employed to investigate the tunnel rupture process. The results show that the high frequency components between 20 and 30 kHz of AE signals are the tunnel rupturing signals under the seismic excitation under such conditions. The tunnel vault and the arch foot are prone to rupture during the seismic excitation, and the initial rupture in the arch foot and vault of the tunnel occur under the horizontal and vertical Kobe wave seismic excitation, respectively, with a maximum acceleration of 0.4 g. After the rupture initiation, the tunnel arch foot continues to rupture in the subsequent working cases regardless of whether the excitation direction is horizontal or vertical, while the tunnel vault does not rupture continuously with the implementation of the subsequent excitations. Moreover, the Kobe seismic wave has a higher degree of damage potential to underground structures than the El seismic wave.

Seismic reliability of steel SMFs with deep columns based on PBSD philosophy

Steel special moment frames (SMFs) represent a common structural solution for buildings in earthquake-prone areas. However, when SMFs are selected by structural engineers, one of their main concerns is to satisfy the permissible drifts recommended by codes. As a common option, the use of deep columns may be a feasible alternative to reduce lateral deformation of SMFs. In this paper, the authors explore the performance of steel SMFs with deep columns by evaluating their seismic reliability. Since earthquake-resistant design is moving from the prescriptive-code to performance-based seismic design (PBSD), an alternative safety approach is integrated with the PBSD philosophy. In this way, SMFs are represented by finite elements and excited by seismic loading incorporating all major sources of nonlinearity as material behavior, geometric deformations, and connections of structural members. The novel approach is developed using the first-order reliability method, response surface method, and an advanced probabilistic scheme. The computational benefits and accuracy of the proposed method are validated using traditional Monte Carlo simulation. The implementation potential is showcased with the numerical evaluation of three 9-story steel SMFs: the first one using columns of medium size and the other two considering deep columns. The seismic reliability is extracted for every model considering serviceability performance functions correlated with performance levels of collapse prevention, life safety, and immediate occupancy. In addition, the contribution of the post-Northridge connection in the steel SMFs is incorporated. Finally, without being too much critical, the use of deep columns in the models of this paper seems to be a step in the right direction to reduce weight, decrease cost, and increase structural reliability. However, it must be stated that deep columns considered in the models have no instability concern because of their low slenderness ratios.

Delineating suitable site for settlement in potential earthquake vulnerable areas using spatial multi-criteria decision analysis in the Sukabumi regency, Indonesia

Land suitability assessment is an important stage in land use planning that guides the direction of optimal land use. The objective of this study was to select a suitable location for settlements in earthquake-prone areas using the integration of the Analytical Hierarchy Process (AHP) and Geographical Information System (GIS). In total, six maps were considered to determine a suitable location for settlements, namely topography, soil, geology, land cover/land use, a regional spatial planning pattern map, and an earthquake vulnerability map. The results showed that in medium earthquake-prone areas, the suitable land area which are available for settlement was 90.25 km2 (46.36% of the total land area available – 194.68 km2). Whereas in highly earthquake-prone areas, the suitable and available land area was 528.11 km2 (70.25% of the total land area in the high vulnerability zone – 751.81 km2). The research proved that AHP and GIS integration is very effective and robust for mapping land suitability in earthquake-prone areas. The results of the analysis can be used by planners to prioritize settlement development in the Sukabumi regency. The methodology developed is recommended to be applied in selecting locations for settlements in other parts of Indonesia.

Earthquake Activities along the Sagaing Fault Zone, Central Myanmar: Implications for Fault Segmentation

In this study, the three terms related to the seismic activities of the Sagaing Fault Zone (SFZ), central Myanmar, of the possible maximum magnitude, return period, and probability of exceedance (POE) of an earthquake of given magnitude were evaluated and mapped using an improved earthquake catalog (free of duplicate records, foreshocks, aftershocks and recording artifacts) and implementation of a statistical approach. As a result, the SFZ was separated into five segments with different seismicity levels. The highest hazard level was found for the segment between Myitkyina–Northern Mandalay, with a likely generation of an Mw 6.4–7.2 earthquake in the next 50 years. For the Naypyidaw–Bago segment, the hazard levels were in the comparatively medium range with a magnitude 6.0–7.0 Mw earthquake return period of 20–50 and 100–200 years, respectively. The Offshore Andaman Sea segment of the SFZ was defined to have the lower hazard, with only a 10% or lower POE of a 7.0 Mw earthquake within the next 50 years. Therefore, effective mitigation plans should be prepared for this area and in particular for the region nearby to the Myitkyina–Northern Mandalay segment as the highest earthquake-prone area.

A geology-based 3D velocity model of the Amatrice Basin (Central Italy)

In this paper we present a new methodological approach which integrates geological and geophysical data into a 3D modelling process to be mainly employed in seismic hazard assessment studies of earthquake-prone areas around the world, as well as in applications for land use and urban planning. As a case study, the reconstruction of a geology-based 3D velocity model of the uppermost hundreds of metres of the Amatrice high-seismic-hazard area is described.The model was constructed using geological (e.g., maps, cross-sections and core-wells) and geophysical (e.g., down-hole, MASW, refraction, and seismic noise measurements) data, which were georeferenced and uploaded into 3D geological modelling software, where faults, stratigraphic boundaries, and geophysical attributes were digitised, checked, hierarchised, and modelled. The performed 3D geological model was parameterised with Vs and Vp velocities and, finally, the environmental noise (i.e., horizontal-to-vertical spectral ratio analysis, HVSR) recorded at some seismic stations was compared with the seismic responses modelled at some nearby control points.In the study area, the proposed geology-based 3D velocity model represents both a new potential geophysical prediction tool for areas devoid of geophysical measurements (i.e. HVSR curves) and a potential input-model for future ground-motion and seismic-wave-propagation simulations aimed at a more precise local seismic response assessment and, consequently, at the development of more realistic seismic hazard scenarios.The model here presented constitutes a first version of the 3D geological-geophysical model for the studied area, which will be improved with new data and more advanced algorithms available in the future.

Effects of processing type on shear modulus and damping ratio of waste tire-sand mixtures

Processed waste tires can be used as additives for geotechnical applications in earthquake-prone areas. The increasing use of waste tires additives requires a better understanding of their dynamic behaviors. Processed waste tires as granular and fiber-shaped rubber particles under the same experimental conditions have not been studied before. The main purpose of this study is to carry out these experiments to determine the effects of two different processing techniques on the shear modulus and damping ratios of the mixtures. It is also the first time that the effects of fiber-shaped rubber particle inclusions are determined in detail. In addition, the results of similar tests using different processed waste tires were evaluated. The effects of the processed waste tires are given by evaluating the literature and this study together. It has been found that depending on the size, aspect ratio and content of the rubber material, the type of processing can significantly affect the dynamic properties of the mixture. The tested materials may be suitable as base isolation material. Of all the studies evaluated, the highest damping ratio was obtained with granulated rubber inclusions.

Shear Wave Velocity Measurements in Tropical Peat Using In-house Device

Many people in the construction industry will agree that peat is a problematic material due to its compressibility behaviour. However, construction on these areas are inevitable because of the scarcity in space and suitable land for development. Hence, there is a need for proper in-situ testing on soil properties before any construction work can be carried out in peat. Shear wave (S-wave) velocity (Vs ) used to compute the small strain shear modulus, (Go ) which is an essential parameter to design structures in earthquake and vibration prone areas. The most versatile method to assess is by measuring shear wave propagation through soil samples using bender elements tests (BET). Currently, BET is limited to laboratory environments, which can be time consuming and expensive. Therefore, a portable device of BET for peat has been proposed in this research which is simple to use and economical. The proposed setup consists of an oscilloscope, digital multimeter, signal generator, signal amplifier, direct current generator and a pair of piezoelectric bender elements. Peak-to-peak method from time domain (TD) technique is implemented as the method to analyse shear waves. To validate the function of the proposed device, different types of soil samples including Ottawa sand, Kaolin S300, Silty loam, Hemic, and Fibric peat were prepared. The peat samples for this study were collected from Pekan and Maran districts in Pahang, Malaysia. With a suitable frequency input from the sine wave generated, the Vs determined from the device was used to compute Go. Results show there is only a less than 10% error in when it was compared with the typical values of tropical peat. The proposed device is also effective to differentiate the type of soil sample when tested. In summary, the proposed in-house device can be used as an indicator and to find out the initial value of Vs and Go in tropical peat soil.

Analysis of time-varying seismic fragility of rigid frame pier of offshore bridge

PurposeAlthough mechanical behavior of rigid frame pier has been clearly recognized, their time-varying seismic performance are yet to be well characterized due to some offshore piers that are eroded by chloride ion and located in earthquake-prone area. In this study, the time-variant seismic fragility analysis was conducted to evaluate seismic performance of rigid frame pier under four damage states with considering the time-varying characteristics of the material.Design/methodology/approachThis paper establishes the nonlinear finite element model for the investigated offshore reinforcement concrete (RC) pier with considering the time-varying durability damage of the materials and defines the damage state, damage position and damaged index of the offshore RC pier. It also analyzes the time-varying seismic fragility of the offshore RC pier by using the capacity demand ratio method in the whole life cycle.FindingsThe results show that chloride induced corrosion has a significant effect on the rigid frame pier and bending capacity of top section is less than that of bottom section. The rate of decline accelerates after the service life reaching 30 years under the coupling of the earthquake and the environmental erosion. In the early years of service, the seismic fragility of the structure changed slowly.Originality/valueThis paper analyzes the influencing factors of seismic performance of rigid structure pier, and analyzes the seismic capacity and seismic performance of rigid structure pier under different service periods.

Mapping of Seismic Vulnerability Potential for Earthquake Disaster Migitation in South Morotai

The geological condition of Morotai Island is influenced by small faults and tectonic activity from several major and minor plates that form the subduction zone, are the Pacific plate, the Philippine plate, the Sangihe plate, and the Moluccas Sea plate. This causes Morotai Island to have a high potential for earthquake hazards. South Morotai is the center of government, services, trade and economy on Morotai Island, and has a high potential for earthquakes. Therefore, an analysis of the distribution of seismic vulnerability values ​​in South Morotai was carried out based on mapping as a disaster mitigation effort in South Morotai. The microtremor method uses the H/V spectral ratio analysis technique to analyze the level of earthquake hazard based on the value of the seismic vulnerability index by considering local soil conditions. The ground frequency value (f0) obtained when measuring microtremor is between 0.6 Hz to 0.7 Hz. The amplitude value (A0) in the South Morotai area is around 1.9 – 5.2 times strengthening. The value of the seismic susceptibility index (Kg) in the study area is calculated based on the value of the basic frequency and amplitude with between 5.9 to 44.8. It was concluded that the distribution of a high Kg index and an earthquake prone area was in Darame Village, Muhajirin Village, and Wawama Village with a Kg value > 20. This area is composed of alluvium consisting of gravel, potential mud, and boulders, so it is classified into soft soil type. Less vulnerable areas are in Gotalamo Village, Daruba Pantai Village, and Darame Village

Consecutive statistical evaluation framework for earthquake forecasting: Evaluating satellite surface temperature anomaly detection methods

Short-term earthquake prediction remains a challenge. In this study, we investigated earthquake predictability using a consecutive statistical evaluation framework (CSEF). Two widely used anomaly detection methods—Z-score (ZS) and Robust Satellite Techniques (RST)—were evaluated using the Atmospheric Infrared Sounder surface temperature data based on global M ≥ 6 earthquakes with focal depths of ≤70 km from 2006 to 2020. Retrospective correlation analyses reveal accuracy and missed detection rates of 80.33% & 19.67% and 80.93% & 19.67% for ZS and RST, respectively. For earthquake forecasting performance in seismically active regions, accuracy rates are within 0–1% and false alarm rates are up to 50–80%. Areas near earthquake-prone regions have the highest accuracy rates. The accuracy rates can be >10% within some regions in Japan and Indonesia. Overall temporal average Matthews correlation coefficients (MCC) range from −0.48 to 0.21; global spatial average MCCs for each day from 2006 to 2020 are between −0.1 and 0.1. After 2012, the ZS method yields higher MCC values than the RST method. Our results confirm the reliability of CESF for assessment of earthquake forecasting capability, and the possibility of forecasting earthquakes at earthquake-prone areas. This approach can be applied to long-term analyses of precursory parameters, anomaly detection methods, and hypotheses, all of which are essential to the ultimate goal of routine and consistent earthquake forecasting.

Experimental Study of Dynamic Characteristics of Tailings With Different Reconsolidation Degrees After Liquefaction

The construction period of most tailing ponds generally lasts for more than 10 years or even decades. During this period, it may be affected by more than one earthquake and is often subjected to vibrations generated by mining activities. The tailings liquefied by earthquakes or vibrations may experience dynamic loads again. Due to the low permeability of tailings, the reconsolidation process of tailings after liquefaction is prolonged. Therefore, changes in the nature of the tailings caused by previous earthquakes will affect the performance of the tailing dam in the subsequent earthquakes. Dynamic triaxial tests and bending element tests were conducted on two kinds of tailings from a copper mine in Southwest China to study this process. The tailing specimens will undergo two consolidation processes and subsequent cyclic loads during the test. The influence of reconsolidation degree, confining pressure, and particle size on the dynamic characteristics and wave velocity of the tailings after liquefaction under cyclic loading was measured. The results show that the reconsolidation degree significantly affects the trend of the excess pore water pressure ratio changing with the increase in the cycle number of loads. The reconsolidation process after liquefaction of tailings will improve its liquefaction resistance. The relationship between the ratio of the cycle number of liquefaction after reconsolidation to the cycle number of first liquefaction and the reconsolidation degree is proposed. In the entire experimental process, the shear wave velocity of the tailings gradually decreases when applying the cyclic load and gradually increases during the consolidation process, including the first consolidation before cyclic loading and reconsolidation after liquefaction. The research results are of great significance to the safe disposal of tailings, especially those in earthquake-prone areas.

Source parameters inversion of the global large earthquakes using 3-D SEM Green's functions: strain Green's function calculation and validation

SUMMARYPrecisely constraining the source parameters of large earthquakes is one of the primary objectives of seismology. However, the quality of the results relies on the quality of synthetic earth response. Although earth structure is laterally heterogeneous, particularly at shallow depth, most earthquake source studies at the global scale rely on the Green's functions calculated with radially symmetric (1-D) earth structure. To avoid the impact of inaccurate Green's functions, these conventional source studies use a limited set of seismic phases, such as long-period seismic waves, broad-band P and S waves in teleseismic distances (30° < ∆ < 90°), and strong ground motion records at close-fault stations. The enriched information embedded in the broad-band seismograms recorded by global and regional networks is largely ignored, limiting the spatiotemporal resolution. Here we calculate 3-D strain Green's functions at 30 GSN stations for source regions of 9 selected global earthquakes and one earthquake-prone area (California), with frequency up to 67 mHz (15 s), using SPECFEM3D_GLOBE and the reciprocity theorem. The 3-D SEM mesh model is composed of mantle model S40RTS, crustal model CRUST2.0 and surface topography ETOPO2. We surround each target event with grids in horizontal spacing of 5 km and vertical spacing of 2.0–3.0 km, allowing us to investigate not only the main shock but also the background seismicity. In total, the response at over 210 000 source points is calculated in simulation. The number of earthquakes, including different focal mechanisms, centroid depth range and tectonic background, could further increase without additional computational cost if they were properly selected to avoid overloading individual CPUs. The storage requirement can be reduced by two orders of magnitude if the output strain Green's functions are stored for periods over 15 s. We quantitatively evaluate the quality of these 3-D synthetic seismograms, which are frequency and phase dependent, for each source region using nearby aftershocks, before using them to constrain the focal mechanisms and slip distribution. Case studies show that using a 3-D earth model significantly improves the waveform similarity, agreement in amplitude and arrival time of seismic phases with the observations. The limitations of current 3-D models are still notable, dependent on seismic phases and frequency range. The 3-D synthetic seismograms cannot well match the high frequency (>40 mHz) S wave and (>20 mHz) Rayleigh wave yet. Though the mean time-shifts are close to zero, the standard deviations are notable. Careful calibration using the records of nearby better located earthquakes is still recommended to take full advantage of better waveform similarity due to the use of 3-D models. Our results indicate that it is now feasible to systematically study global large earthquakes using full 3-D earth response in a global scale.

Multicriteria Decision-Making Methods in Selecting Seismic Upgrading Strategy of High-Rise RC Wall Buildings

Reinforced concrete (RC) structural walls are widely used in high-rise structures in earthquake-prone areas. Damaged by the earthquakes in the past decades, these buildings need retrofitting in order to increase the resilience of buildings with concrete shear walls. This study aimed to investigate the retrofitting of high-rise RC wall buildings using energy dissipation devices. To this end, a total of four buildings with 15, 20, 25, and 30 stories equipped with concrete shear walls as their lateral load-resisting system were retrofitted using passive seismic control systems. The buildings were subjected to the set of the far-field and near-field records presented in the FEMA standard (P-695), and an index was defined to relate the structural responses of the building, such as drift, acceleration, velocity, displacement, and base shear, to the earthquake records. For this purpose, numerical models, which have been validated with the experimental results, have been performed. The resulting index values were considered as the criteria, and the passive systems were ranked by the efficient Multicriteria Decision Making (MCDM) method. Based on the results from the MCDM method and using the considered criteria, friction damper was ranked first among the available energy dissipation devices for high-rise RC wall buildings.

Seismic Assessment and Retrofitting of Existing Road Bridges: State of the Art Review.

The load-carrying capacity assessment of existing road bridges, is a growing challenge for civil engineers worldwide due to the age and condition of these critical parts of the infrastructure network. The critical loading event for road bridges is the live load; however, in earthquake-prone areas bridges generally require an additional seismic evaluation and often retrofitting in order to meet more stringent design codes. This paper provides a review of state-of-the-art methods for the seismic assessment and retrofitting of existing road bridges which are not covered by current design codes (Eurocode). The implementation of these methods is presented through two case studies in Croatia. The first case study is an example of how seismic assessment and retrofitting proposals should be conducted during a regular inspection. On the other hand, the second case study bridge is an example of an urgent assessment and temporary retrofit after a catastrophic earthquake. Both bridges were built in the 1960s and are located on state highways; the first one is a reinforced concrete bridge constructed monolithically on V-shaped piers, while the second is an older composite girder bridge located in Sisak-Moslavina County. The bridge was severely damaged during recent earthquakes in the county, requiring urgent assessment and subsequent strengthening of the substructure to prevent its collapse.

Ductility and cracking behavior of reinforced coconut shell concrete beams incorporated with coconut shell ash

Coconut shell concrete beams containing coconut shell ash are a feasible alternative to traditional reinforced concrete beams in structural applications. Coconut shells in reinforced concrete beams are essential in earthquake-prone areas because of their ductility properties, which contribute to enhancing earthquake resistance. This research investigates the flexure, ductility, shear, and cracking behavior of reinforced concrete beams made from the incorporation of a minimum quantity of untreated coconut shell particles (CSP) at 5% substitution of coarse aggregate (CA) modified with coconut shell ash (CSA) at 10% substitution of Ordinary Portland cement (OPC). Two beams were evaluated for flexural, strain, ductility, and cracking behavior. In contrast, the other two were evaluated for flexural, shear, strain, ductility, and cracking behavior by repositioning the loading point to the distance of 200 mm close to the support. In comparison to control beams evaluated for flexural, shear, strain, ductility, and cracking behavior, the ductility ratio of concrete beams with 10% CSA and 5% CSP improved by 8.8%. The ductile improvement was observed with a 17.3% decrease in flexural load. The shear capacity of reinforced concrete beams with 10% CSA and 5% CSP improved compared to the reference literature in the study. Finally, it was discovered that combining 10% CSA and 5% CSP in reinforced concrete beams can improve ductility without significantly reducing ultimate failure load.

Comparative study of Multistoried Building with X & Inverted V Bracing

The most suitable technique in order to increase the performance and the lateral stability of the RC Frame building situated in earthquake prone areas is the use of steel bracings. In this paper comparison of seismic behavior of G+15 multistoried building situated in zone 4 on medium soil has been carried out on 3 different models by installing different types of bracing i.e X bracing and inverted V bracing. The designed structure should have enough lateral stability in order to resist the lateral force during the seismic shaking, and the parameters such as the storey drift should be within the permissible limits as per the IS 1893-2016. The use of Steel Bracing in Reinforced concrete structure not only helps to reduce the lateral loads during the earthquake but also helps us to reduce the section size of the reinforced concrete structures. In this paper 3 models have been analysed- Model no 1 – G+15 building without steel bracing, Model no 2- G+15 building with X bracing, Model no 3 – G+15 building with inverted V bracing, All the 3 models have been analysed with the help of STAAD PRO V8i software and comparison between these models have been carried out based on 3 seismic parameters such as Storey Drift, Storey Displacement and Base shear. Keywords Storey Drift, Storey Displacement, Base Shear, Seismic Analysis, Steel Bracing.