Earthquake-resistant Construction Research Articles

Structural damages observed in buildings after the January 24, 2020 Elazığ-Sivrice earthquake in Türkiye

Türkiye is located in the most active earthquake zones with the shortest return period. Consequently, it has exposed several destructive earthquakes that caused significant casualties and extensive structural damage during recent decades. Elazığ-Sivrice earthquake was one of them. The earthquake had a magnitude of Mw 6.8. It occurred in the Sivrice district of Elazığ province in eastern Türkiye on 24 January 2020. Many buildings were collapsed or severely damaged. A total of 41 people died and at least 1607 people were injured. This study aims to present the different types of structural damage observed immediately after the earthquake. Many structural insufficiencies and errors such as non-seismic reinforcement detailing, non-conforming earthquake-resistant construction techniques, poor quality of concrete and poor workmanship are the main reasons for the extensive damage observed in many past earthquakes in Türkiye. In addition, geotechnical inspections also indicated that soil settlement might be prevented by building basement floors in the areas that were observed. The results of the study have shown that not enough lessons have been learned from previous earthquakes. Because of this, structural engineers must closely follow structures while they are built, and well-trained staff must be employed during the construction process.

Material properties of palm bark Cross Laminated Timber (CLT) infill wall for earthquake-resistant reinforced concrete buildings: a preliminary investigation

This study conducts a preliminary investigation to determine the material properties of Cross- Laminated Timber (CLT) made from the bark of unproductive palm trunks. One-third of the lower part of palm trunks, aged over 20 years, was used for this purpose. CLTs were created by laminating palm boards into three and five layers, each measuring 200 mm x 20 mm x 1500 mm. A chemical epoxy was employed for lamination. The palm stems were dried in an oven at 110°C for 24 hours. Test results revealed a water content of 6.79% and a specific gravity of 0.23 gr/cm3 in oil palm stems. According to ASTM D143-94- 2005 and JIS Z210-21118 standards, wood's acceptable moisture content ranges from 12% to 20%. Given its low specific weight and minimal water content, palm oil trunks, including infill walls, show promise for use in earthquake-resistant construction.

Crossbars of frame buildings when changing the sign of forces

A large number of reinforced concrete frame buildings are located in seismically dangerous regions. In case of seismic impacts plastic strains and local destructions occur in elements of such buildings, which influence sufficiently on their bearing capacity and stress-strain state when changing the sign of internal forces. This fact is not taken into account in current Russian norms on earthquake-resistant construction. The numerical research of reinforced concrete beams behavior under action of alternating load with regard to elastic-plastic properties of concrete and reinforcement has been conducted. The evaluation of influence of plastic strain maximum value in tensed reinforcement on the relative bearing capacity of the beam when changing the force sign and on the limit value of coefficient of plasticity corresponding to the destruction of compressed zone of concrete has been made. The comparison of results of numerical simulation with the results of experimental tests of beams with the same parameters has been made, which has demonstrated good convergence of numerical calculations with experimental data both in terms of bearing capacity and deformations for plasticity coefficients less than 2.5. During the experiment it has been found that when changing the sign of internal forces the through cracks form in bending reinforced concrete elements throughout the entire section height, which close afterwards if the coefficient of plasticity for reinforcement deformations does not exceed 2.5. For greater values of coefficient of plasticity the through cracks closing doesn’t take place until the destruction of the specimens due to the rupture of reinforcement bars. According to the results of the study it was concluded, that the decrease by 40% of relative bearing capacity of beams compared with reference samples as the increase of coefficient of plasticity in the first semi cycle of loading takes place. Also with the increase of the coefficient of plasticity the three times decrease of the limit values of coefficients of plasticity, corresponding to destruction of compressed concrete, when changing the sign of forces is observed. The numerical calculations of beams models for 10 and 50 alternating load cycles have been conducted with cycle asymmetry coefficient equal to -1. The conclusion has been made that under the action of alternating load with the number of loading cycles not exceeding 50 and for maximum values of coefficient of plasticity not exceeding 1.62 the insignificant decrease of relative bearing capacity of beams, not exceeding 10%, takes place.

Optimization of the assembly of cross-truss structures

As a result of a review and analytical search based on patent research and development, a new method of assembling cross-truss structures in relation to modules of the Pyatigorsk type has been optimized. The scope of its rational application is outlined, including the construction of new facilities and the reconstruction of existing buildings. The efficiency of assembling such structures in earthquake-resistant construction, including flexible upper floors capable of dampening mechanical vibrations, is noted. The continuation of flexible manufacturing technology in this method of assembly has been revealed, when the entire set of cross-truss structures of full factory readiness is mounted on the construction site in the project position. At the same time, all assembly and welding, transport, installation operations in shop and building conditions are performed by the same personnel due to their high qualifications, which ensures the necessary and sufficient competitiveness under the most difficult conditions of the economic conjuncture.

Оперативная оценка последствий разрушительного землетрясения в Турции

In this article, based on the analysis of the seismotectonic and seismological situation, an assessment of the consequences of the earthquake in Turkey is carried out. Geotectonic processes in the region, the largest earthquakes in the recent history of Turkey are considered. A comparative analysis of the standards for earthquake-resistant construction in Turkey, Russia and the CIS countries was carried out.

О причинах возникновения и последствиях двух разрушительных землетрясений в Турции 06.02.2023 г.

Using the developed geoinformation system “Prediction”, an analysis was made of information available from the media on two devastating earthquakes in the Türkiye that occurred in the western segment of the East Anatolian fault on February 6, 2023. The possibilities of recognizing signs of the preparation of earthquake data by means of medium-term forecasting developed for the Baikal rift zone, which are important for assessing seismic hazard and seismic risk, are discussed. Based on the analysis of the consequences of the large-scale destruction of residential and industrial infrastructure in the Türkiye, the causes of the huge damage to the country's economy caused by earthquakes, which are largely due to unfavorable seismotectonic conditions and urbanization problems that arose as a result of insufficient compliance with the necessary requirements and norms of earthquake-resistant construction, are considered.

Overview of “Guidelines and Commentaries for Earthquake-Resistant Construction Methods for Waterworks Facilities 2022” published by JWWA

Overview of “Guidelines and Commentaries for Earthquake-Resistant Construction Methods for Waterworks Facilities 2022” published by JWWA

Improving Earthquake Resistant Design and Construction in India

New materials and structural systems are being introduced in construction profession every day either to replace conventional materials whose availability is becoming scarce or to improve the efficiency of construction. New systems are also being introduced to cater to new demands in functionality and aesthetics. While Indian researchers have kept pace with the theoretical aspects of earthquake resistant design, the practical aspects are hardly touched upon since they require testing and implementation in practice. The current codes are prescriptive about the general requirements for strength and detailing and so are inadequate to define and assess the performance objectives of specific structural systems. Consequently, the gap between academics and profession has been widening and has reached extreme proportions and there is an urgent need to revive applied research in earthquake engineering to evaluate seismic performance of practical systems. In this paper, the work carried out by the author and his students at IIT Madras on seismic design and tests carried out on masonry, reinforced concrete, structural steel, steel-concrete composite, cold-formed steel, semi-rigid frames of steel and composite construction and industrial rack systems are reviewed. The importance of understanding the details of the seismic behaviour of these system towards improving the performance is emphasized.

Assessment of seismic resistance of multi-storey buildings under seismic impacts on weak subsidence soils

Under the influence of dynamic and static loads, the volumes of weak soils in the base change due to a decrease in porosity. In this regard, studies of the stability of the building under seismic influences, the bases of which are elastic-plastic layers, have been carried out. As a result of the research carried out in this paper, an equation of ground motion was obtained to determine the general angle of inclination of the building, taking into account the seismic impact characteristic of the construction site and the characteristics of the building itself. An increase in the risk due to the loss of stability of the base due to the possible slope of the building is shown. The mechanism of soil weakening, which leads to the overturning of buildings, is analyzed and justified. The parameters affecting the kinematic characteristics of buildings and structures are shown. It is determined that an elastic system consisting of a building and a base has one-way connections between the foundation and the base, which are removed under the influence of seismic forces in certain areas of the foundation sole, where the static load is insignificant. Removing the links causes a change in the rigidity of the system. The center of gravity and the center of mass are shifted by a certain distance, therefore, there are changing fluctuations. The range of vibrations in this case depends on the ratio of the natural frequencies of buildings and seismic waves. It is known that when a building under the influence of external forces receives a certain slope relative to the vertical axis, then there is a decrease in the load, a dependence is obtained to determine the load reduction coefficient. The paper considers a practical solution to the problem of stability on the example of a 50-meter building. Based on the general principles of earthquake-resistant construction in the calculation of overturning, several calculations of buildings were carried out using the initial data for frequent and weak impacts, moderate strength and rare strong impacts. The results of the research can be applied to the calculations of multi-storey and high-rise buildings built on weak deformable soils, along with other calculations that allow increasing seismic resistance.

The Planked Timber Vaults Built in Seismic Zones of South America between the 17th and 18th Centuries: History and Construction Analysis

ABSTRACT The western coast of South America is a territory continually exposed to earthquakes, where architects had to experiment proposals that would allow them to maintain the safety of their buildings. Among the different solutions for earthquake-resistant constructions, planked timber vaults appeared in South American religious architecture during the 17th century. This paper explains how the construction technique of these vaults arose and developed in a context conditioned by earthquakes. For the study, architectural surveys of the different variants of South American vaults were conducted, which were confronted with data from archives and historical texts, to later be expressed graphically through the drawing reading method. This method is important to transfer textual information from historical documents to contemporary graphic language and permit to learn more about the architectural heritage, like the construction characteristics of the planked timber vaults and understand the structural criteria followed by the ancient master builders.

Organized self-help housing in Pachacútec, Peru: Training women's groups in earthquake resistant housing construction

Ciudad Pachacútec is a suburban development scheme north of Lima, where deficiencies were great from the start. The main problem was the population’s safety in the sandy and arid urban landscapes, which are prone to earthquakes. The main objective of the NGO Estrategia - together with the municipality of Ventanilla - was to provide the self-builders with technical and organizational knowledge to improve housing quality. The NGO has developed effective programs to support women's groups in building earthquake-resistant houses. The result was that building materials were produced locally by households that were also trained in construction technology. Some families working together in groups, were able to start businesses. The developed model for earthquake resistant housing in New Pachacútec is effective and can be used in other areas alongside Peru’s Pacific coast, that are prone to earthquakes.

Finite element analysis of behavior and ultimate strength of composite column

Abstract Composite sections are found to be a novel technique in modern day scenario of construction. This stands tall than the ordinary and conventional type of constructions. Columns as a structural element play a vital role in structural frame. This research comments on the behavior of composite columns. The main objective of this study is to analyze the behavior of steel-encased concrete composite columns as experimentally under axial compression and the mode of failure under ultimate failure and yield point. The steel-concrete composite system combines the formability and rigidity of reinforced concrete with the ductility and strength of structural steel to meet the demand for earthquake-resistant constructions. Three specimens were chosen for this study: one was a composite column, the other two were ordinary RC columns and structural steel columns. The raw materials' natural properties are assessed. As a result, material testing for cement, fine aggregate, and coarse aggregate was completed, as well as a concrete mix design. A comparative analysis of the local and post-local buckling behavior of different composite sections has been studied and the column sections have been designed according to Eurocode 4 (ENV 1994) to determine the plastic resistance of the section. These three specimens underwent compression test and the results are tabulated and compared. The corrosion resistance and fireproof nature (resistance to fire at higher temperatures) that are transmitted into the member are related to the steel being encased within the concrete. These are the two major drawbacks of any steel construction combined with an earthquake-resistant structure. Rather than a traditional steel construction, earthquake structures benefit from this type of load handling capabilities. The portion can be used before it completely collapses if proper design factors are taken into account.

On the use of small-scale wooden elements in earthquake-resistant construction

On the use of small-scale wooden elements in earthquake-resistant construction

Earthquake-resistant Techniques in the Etna Area (Sicily) after the Earthquake of 1818

ABSTRACT The purpose of this paper is to offer a contribution to the topic of earthquake-resistant construction techniques in Sicily in the nineteenth century, with particular reference to the building systems used after the earthquake that hit the Etna area between 20 February and 1 March 1818. Our research is based on an overlapping study of the bibliographic sources and archive documentation supported by direct analysis of the buildings. The aim is to delve into the building techniques used in the reconstruction by analysing a series of significant case studies. After examining the effects of the 1818 earthquake in the Etna area and its influence on the local technical culture, attention was placed on the systems used to reinforce and restore the buildings, highlighting some important innovations in determining anti-seismic project criteria aimed at decreasing the seismic vulnerability of buildings.

COMPARISON OF MRF AND CBF STRUCTURAL RESPONSE TO EARTQUAKE IN OFFICE BUILDING SURABAYA

Indonesia is a country that prone earthquakes. Therefore, knowledge of earthquake-resistant building construction is needed in reducing the risk of damage caused by earthquakes. There are several methods of earthquake-resistant construction planning, one of which is the pushover analysis method. Pushover is a nonlinear static analysis method in which the structure is subjected to gravity loading and displacement-controlled lateral loads which continue to increase through elastic and inelastic behavior until the final condition. One of the popular construction materials in structural planning is steel construction, which has a uniform structure, lightweight, strong, and easy to work with. In modeling earthquake-resistant structures, several popular models are the MRF and CBF models. MRF is a structural configuration model configured on beams that are firmly connected to columns. Based on a rigid beam-column connection, the moment frame cannot be moved laterally without bending the beam or column depending on the connection geometry. Results The case study on the comparison of the two structural models concluded that in the design of earthquake-resistant steel structures using the pushover method, it was found that the MRF structure had higher ductility than the CBF, namely 2.1:1.6.

ASSESSMENT OF THE INFLUENCE OF THE ROTATIONAL COMPONENTS OF SEISMIC ACTION ON THE SSS OF A MULTISTOREY REINFORCED CONCRETE BUILDING

The urgent task of earthquake-resistant construction is to improve the methods of calculating the seismic effect. Currently, most calculations for seismic effects are made taking into account only the translational components of the earthquake. However, seismic soil rotations make a tangible contribution to the dynamic response of structures that are sensitive to the wave effect of seismic impact. Modern studies show that building structures have a spatial nature of work, and in calculations for seismic loads, in addition to three translational components, it is necessary to consider the impact on buildings and structures from additional three rotational components. The purpose of this work is to assess the influence of rotational components on the stress-strain state of a multielement reinforced concrete building. In the course of the work, calculations of a reinforced concrete building were made without taking into account and taking into account the rotational components of the seismic impact, based on the results of which a comparative analysis was made. The calculation for the earth-quake was performed by an explicit direct dynamic method of central differences in the LS-DYNA software in six settings: the action of the translational component is set along the X axis; the action of the translational com-ponent is set along the X axis and rotational component – relative to the Y axis; the action of the translational component is set along the Y axis; the action of the translational component is set along the Y axis and rotational component – relative to the X axis; the impact of three translational components; the action of three translational and three rotational components. As a result of a comparative analysis of the obtained displacements and stresses, it was concluded that taking into account rotational components does not make a tangible contribution to the SSS of the building under consideration.

Coseismic surface rupture characteristics and earthquake damage analysis of the eastern end of the 2021 MS 7.4 Madoi (Qinghai) earthquake

At 02:04 on May 22, 2021, an MS 7.4 earthquake occurred in Madoi County in Qinghai Province, China. This earthquake is the largest seismic event in China since the 2008 MS 8.0 Wenchuan earthquake. Thus, it is critical to investigate surface deformation and damage in time to accurately understand the seismogenic structure of the Madoi earthquake and the seismogenic capacity of the blocks in this region. This study focuses on the Xuema Village, located at the eastern end of the coseismic surface ruptures produced by the event, and assesses the deformation and seismic damage in this area based on field surveys, UAV photogrammetry, and ground penetrating radar (GPR). The results indicate that the rupture scale is substantially smaller at the eastern end of the rupture zone compared to other segments. En echelon type shear tensile fractures are concentrated in a width range of 50–100 m, and the width of single fractures ranges from 20 to 30 cm. In contrast, the degree of seismic damage significantly increases at this site. All of the brick and timber houses are damaged or collapsed, while the steel frame structures and the color steel houses are slightly damaged. More than 80% of the bridge decks on the Changma River Bridge collapse, similar to the terraces along the Youerqu and Changma Rivers and the cut slopes of Provincial Highway S205. We infer that the seismogenic fault of the Madoi earthquake exerts a tail effect in this segment. The tension zone has led to a reduction at the eastern end of the rupture zone, causing shaking damage. Local topography and buildings without earthquake-resistant construction along the strike of the rupture zone have undergone different levels of seismic damage.

Structural Concept Features of Suspended Structures for Seismic Areas

The key task of the building design is the comprehensive elimination of hazards arising from various impacts on buildings, including seismic ones. Recently, new structural systems have been developed to ensure the earthquake resistance of buildings, as well as the already known ones are being improved. One of the types of structural systems that can be used in seismically active areas are buildings with suspended structures. There are many design solutions for buildings with suspended structures that differ in the type of supporting structure, suspension system and geometric shape. The possibility of using suspended structures under dynamic influences is explained by a load decrease in the load-bearing elements of the building due to the flexibility of these structures, as well as a large natural period of oscillations of buildings with suspended structures. Some aspects of the use of buildings with suspended structures are not fully understood, which prompted a study of the behavior of these buildings using various structural solutions in earthquake conditions. For the effective use of these structures in the practice of earthquake-resistant construction, an important issue is to understand the behavior of suspended structures under seismic influences of a wide frequency spectrum. The results of the study are presented in the paper.

Survey on Major Worldwide Regulations on Seismic Base Isolation of Buildings

Base isolation solutions are efficient alternatives for seismic protection of buildings and for enhancing resilient capacity. Currently, seismic isolation is focused principally on the critical infrastructure of public health, transportation, education, etc. Despite these considerations, the current worldwide implementation of this technology is still insufficient. A crucial step to be taken into the promotion of any earthquake‐resistant construction technique is the development of design codes that, although being inspired in the major international regulations, account for the local seismic effects, among other factors. With the aim of assisting code developers, this work analyzes and compares the code requirements for seismic base isolation in Japan, China, Russia, Italy, USA, and Chile. Two prototype seismically isolated hospital buildings located in high and medium seismicity zones (Los Angeles and New Mexico, respectively) were analyzed and designed with the examined codes. It is concluded that there are high differences among some of their requirements even though the technology used is the same.

On the necessity to update regulatory documents in the field of earthquake-resistant construction

On the necessity to update regulatory documents in the field of earthquake-resistant construction