Earthquake Resistant Design Of Buildings Research Articles

New Lateral Force Distribution for Seismic Design of Structures Based on Seismic Demand Ratio

The design of earthquake-resistant buildings starts with defining the maximum lateral earthquake forces or their resultant. The amount of these forces depends on various factors, including coefficient of system behavior which depends on over strength and its ductility. In this study, a method is proposed in order to design an earthquake-resistant system in which the distribution of lateral forces is adjusted based on equal distribution of the seismic demand ratio in structural elements for the optimum use of seismic capability of the structure. To this end, three types of 4-, 7-, and 10-story structures are Applied. Firstly, the above-mentioned structures are designed based on gravity loads and consequently analyzed based on linear and nonlinear dynamic analyses, applying the accelerograms of some major earthquakes. Pursuant to that, the average loading ratio to the allowed capacity of the elements of each story in linear analysis and the average ratios of plastic rotations to the allowed capacity of elements in nonlinear analysis are applied as the modified shear ratio in the Iranian National Seismic Code. On that account, the new lateral loading distribution is measured and identified. Based on this new distribution, the above-mentioned structures are designed and their seismic behaviors are identified, applying linear and nonlinear dynamic analyses of the same accelerograms. The findings indicate an ameliorated seismic behavior of the beams and the columns. Moreover, the distribution of the seismic demand ratios attains more uniformity along the height of the structures.

Computer-aided design of civil building structural connections constructed in earthquake-prone regions

More than 300000 earthquakes occur worldwide every year. The main goal of the earthquake-resistant design of buildings and structures in earthquake-dangerous regions is to assure the safety of people and the security of material assets. Significant damage or even complete collapse of buildings are not uncommon because of the inadequate strength of their structural framing elements and connections. The modern approach in the theory of seismic design is in the avoidance of using brittle materials in construction, as well as in regarding as acceptable a local damage that does not lead to the collapse of the entire structure. Often when designing a reinforced concrete building, an engineer is mainly concerned with a strength of a structure, while not paying enough attention to its ductility and ability to absorb the energy. Construction of buildings and their connections based on the structural composite steel fiber concrete in earthquake-dangerous regions is very promising due to the superior ability of this material to resist to static and dynamic loading, which could be controlled by an engineer.

Performance of Single Friction Pendulum bearing for isolated buildings subjected to seismic actions in Vietnam

Using structural control technology in earthquake resistant design of buildings in Vietnam is very limited. In this paper, a performance evaluation of using Single Friction Pendulum (SFP) bearing for seismically isolated buildings with earthquake conditions in Vietnam is presented. A two-dimensional (2-D) model of the 5-storey building subjected to earthquakes is analyzed in time domain. Accordingly, the model is analyzed for 2 cases: with and without SFP bearing. The ground acceleration data is selected and scaled to suit the design acceleration in Hanoi followed by the Standard TCVN 9386:2012. It is shown that the seismically isolated buildings gets the performance objectives while achieving an 91% reduction in the base shear, a significant decrease in the inter-story drift and absolute acceleration of each story. A post-publication change was made to this article on 9 Jul 2020 to remove an author.

Evaluación del grado de daño en la ciudad de pasto (colombia) a causa de sismos históricos

San Juan de Pasto, capital of the Department of Narino (Colombia), is located in a high seismic hazard region, according to the Regulations for Earthquake Resistant Design of Buildings. The city has been affected by several earthquakes throughout its history associated with the main seismotectonic sources in the country such as the Algeciras, Romeral, and Afiladores fault systems and the subduction zone. A review of the historical earthquakes that have significantly affected (intensity ≥7 on the EMS-98) San Juan de Pasto city was carried out to contextualize, classify and evidence recurrent damage, which provides an approach to determine possible site effects in the city. There are other issues that also influence the site effects such as the soil condition and topography of the area, but these are not considered in this study. The earthquakes selected were on January 20, 1834, October 26, 1935, and July 14, 1947, which significantly damaged many structures in the city. For every case, the type of affected structure, its constructive vulnerability and the degree of damage were analyzed, taking into account the historical context of each period. These data were georeferenced on the city map, and it was observed that there are common areas that have been affected by all the seismic events.

Development of Nationwide Vs30 Map and Calibrated Conversion Table for Indonesia using Automated Topographical Classification

A nationwide Vs30 map for Indonesia was developed based on automated topographic classification from 90-m grid digital elevation data and their correlation with Vs30. Automated topographic classification has been proposed by Iwahashi and Pike (2007) and a procedure to convert topographic class into Vs30 maps has been developed by Imamura and Furuta (2015) based on Vs data from J-SHIS (Japan Seismic Hazard Information System). In order to be suitable for Indonesia, calibration work according to Imamura and Furuta's procedure should be conducted since the geotechnical conditions in Japan may not be the same as in Indonesia. This paper presents adjustment of the Vs30 correlation by Imamura and Furuta to convert topographic class into Vs30 and construct a Vs30 map of Indonesia. This correlation was calibrated by using Vs data from BMKG (Indonesian Agency for Meteorological, Climatological, and Geophysics) as well as standard penetration test logs that were collected by the authors. Utilization of local field measurement data will certainly enhance the reliability of the Vs30 map. The developed nationwide Vs30 map will be very useful for disaster mitigation programs and for preliminary design of earthquake resistant buildings and infrastructure in Indonesia.

Real-Time Swing-up and Stabilization Control of a Cart-Pendulum System with Constrained Cart Movement

Abstract The cart-pendulum system is a typical benchmark problem in the control field. It is a fully underactuated system having one control input for two degrees-of-freedom (DOFs) system. It has highly nonlinear structure, which can be used to validate different nonlinear and linear controllers and has wide range of real-time (realistic) applications like rockets propeller, tank missile launcher, self-balancing robot, stabilization of ships, design of earthquake resistant buildings, etc. In this work, modeling, simulation and real-time control of a cart-pendulum system is performed. The mathematical model of the system is developed using Euler-Lagrange approach. In order to achieve a more realistic model, the actuator dynamics is considered in the mathematical model. The main aim of this work is to investigate the performance of two different control strategies- first to swing-up the pendulum to near unstable equilibrium region and second to stabilize the pendulum at unstable equilibrium point. The swing-up problem is addressed by using energy controller in which cart is accelerated by providing a force to the cart with a AC servo motor with the help of timing pulley arrangement. The initial velocity of the cart is taken into account to confirm swing-up in the restricted track length. The cart displacement in the restricted track length is verified by simulation and experimental test-run. The regulation problem of stabilization of pendulum is addressed by developing the controller using Pole Placement Controller (PPC) and LQR Controller (LQRC). Both the control strategies are performed analytically and experimentally using the Googoltech Linear Inverted Pendulum (GLIP) setup. The analytical results, simulated in MATLAB and SIMULINK environment, are found in close agreement with the experimental results. In order to demonstrate the effect of both the stabilizing controllers on the performance of the system, comparison of the experimental results is reported in this work. It is demonstrated experimentally that LQR controller outperforms the Pole Placement controller, in terms of reduction in the oscillations of the inverted pendulum (56 %), as well as the magnitude of maximum control input (66.7 %). Further, robustness of the closed-loop system is investigated by providing external disturbances.

Communicating Earthquake Preparedness: The Influence of Induced Mood, Perceived Risk, and Gain or Loss Frames on Homeowners' Attitudes Toward General Precautionary Measures for Earthquakes.

Despite global efforts to reduce seismic risk, actual preparedness levels remain universally low. Although earthquake-resistant building design is the most efficient way to decrease potential losses, its application is not a legal requirement across all earthquake-prone countries and even if, often not strictly enforced. Risk communication encouraging homeowners to take precautionary measures is therefore an important means to enhance a country's earthquake resilience. Our study illustrates that specific interactions of mood, perceived risk, and frame type significantly affect homeowners' attitudes toward general precautionary measures for earthquakes. The interdependencies of the variables mood, risk information, and frame type were tested in an experimental 2 × 2 × 2 design (N = 156). Only in combination and not on their own, these variables effectively influence attitudes toward general precautionary measures for earthquakes. The control variables gender, "trait anxiety" index, and alteration of perceived risk adjust the effect. Overall, the group with the strongest attitudes toward general precautionary actions for earthquakes are homeowners with induced negative mood who process high-risk information and gain-framed messages. However, the conditions comprising induced negative mood, low-risk information and loss-frame and induced positive mood, low-risk information and gain-framed messages both also significantly influence homeowners' attitudes toward general precautionary measures for earthquakes. These results mostly confirm previous findings in the field of health communication. For practitioners, our study emphasizes that carefully compiled communication measures are a powerful means to encourage precautionary attitudes among homeowners, especially for those with an elevated perceived risk.

Evaluation of the seismic performance of special moment frames using incremental nonlinear dynamic analysis

In this paper, the incremental nonlinear dynamic analysis is used to evaluate the seismic performance of steel moment frame structures. To this purpose, three special moment frame structure with 5, 10 and 15 stories are designed according to the Iran\'s national building code for steel structures and the provisions for design of earthquake resistant buildings (2800 code). Incremental Nonlinear Analysis (IDA) is performed for 15 different ground motions, and responses of the structures are evaluated. For the immediate occupancy and the collapse prevention performance levels, the probability that seismic demand exceeds the seismic capacity of the structures is computed based on FEMA350. Also, fragility curves are plotted for three high-code damage levels using HASUS provisions. Based on the obtained results, it is evident that increase in the height of the frame structures reduces the reliability level. In addition, it is concluded that for the design earthquake the probability of exceeding average collapse prevention level is considerably larger than high and full collapse prevention levels.9.

Plastic design of eccentrically braced frames with shear panels

This paper introduces a new earthquake-resistant building design featuring eccentrically braced frames with steel wall shear panels. It also proposes closed-form expressions for analysis and extension of the existing failure mode control design method for the new structural system. Closed-form equations for internal forces were obtained, and probable failure mechanisms and corresponding lateral load multipliers for secondary effects were identified. Selection of member profiles was completed by the mechanism equilibrium curve concept. Pushover modelling was then performed with plastic hinge distribution corresponding to failure mechanisms. Only small differences were found between the analytical and modelled values of lateral force multipliers, meaning that the closed-form equations are a valid alternative approach for plastic analysis and design of eccentrically braced frames with shear panels.

Advancing integrated STEM learning through engineering design: Sixth-grade students’ design and construction of earthquake resistant buildings

ABSTRACTAs part of a 3-year longitudinal study, 136 sixth-grade students completed an engineering-based problem on earthquakes involving integrated STEM learning. Students employed engineering design processes and STEM disciplinary knowledge to plan, sketch, then construct a building designed to withstand earthquake damage, taking into account a number of constraints. On testing, students redesigned to build an improved structure. Using a framework of design processes, we report on the students' capabilities in planning, creating annotated sketches, and transforming these into 3D models. An understanding of core STEM concepts was apparent in their responses, including shape properties, stability, rigidity, balance, strength, and engineering techniques. Group problem solving involved moving iteratively between design phases, frequently revisiting problem scoping, being cognizant of the problem goal, boundaries and constraints, and appreciating design sketches as guiding constructions. Students were also observed to consider a number of problem components simultaneously, indicating their capabilities in handling the complexity of the task.

Should accidental eccentricity be eliminated from Eurocode 8?

Modern codes for earthquake resistant building design require consideration of the so-called accidental design eccentricity, to account for torsional response caused by several factors not explicitly considered in design. This provision requires that the mass centres in the building floor be moved a certain percentage of the building's dimension (usually 5%) along both the x and y axes and in both positive and negative directions. If one considers also the spatial combinations of the two component motion in a dynamic analysis of the building, the number of required analyses and combinations increases substantially, causing a corresponding work load increase for practicing structural engineers. Another shortcoming of this code provision is that its introduction has been based primarily on elastic results from investigations of oversimplified, hence questionable, one story building models. This problem is addressed in the present paper using four groups of eccentric braced steel buildings, designed in accordance with Eurocodes 3 (steel) and 8 (earthquake design), with and without accidental eccentricities considered. The results indicate that although accidental design eccentricities can lead to somewhat reduced inelastic response demands, the benefit is not significant from a practical point of view. This leads to suggestions that accidental design eccentricities should probably be abolished or perhaps replaced by a simpler and more effective design provision, at least for torsionally stiff buildings that constitute the vast majority of buildings encountered in practice.

Seismic Capacity Assessment of Existing RC Buildings in The Sudan by Using Pushover Analysis

Recently, the evaluation of seismic performance of existing buildings has received a great attention. Current research works and observations indicate that The Sudan have low-to-moderate seismic regions. Most of existing buildings are designed only for gravity load. The objective of this paper is to assess the seismic performance of existing RC buildings in The Sudan. Four typical buildings were investigated using pushover analysis according to ATC-40. They were designed according to the Regulations for earthquake-resistant design of buildings in Egypt (ESEE) and International Building Code (IBC2012). Results showed that the buildings designed considering by ESEE and IBC2012 loads were found adequate and satisfied the Immediate Occupancy (IO) acceptance criteria according to ATC-40. The comparison of the pushover curve shows that the stiffness of frames is larger when using ESEE Regulations compared to the IBC2012 design. This means that ESEE design procedure provides a greater capability to resist seismic load than the IBC2012 design.

Investigation of the relationship between ground and engineering bedrock at northern part of the Gulf of İzmir by borehole data supported geophysical works

Loss of life and property that may occur as a result of a possible earthquake can be reduced by earthquake resistant building designs. In order to investigate possible ground motion amplification in earthquake resistant building design, relationship between the ground and engineering bedrock must be ensured. In order to provide this relation, structure, basic characteristics, and thickness of the ground are investigated. In this context, calculating ground transfer function, obtaining horizontal earthquake acceleration changes, calculating Vs values and defining the engineering bedrock are necessary. In this study, Menemen plain, the nothern part of Izmir metropolitan located in active earthquake zone and its immediate vicinity have been examined to define the structure, ground, engineering and bedrock relation. In this context, Menemen plain has been investigated by geophysical methods, which are supported with borehole data (microtremor, MASW – multichannel analysis of surface waves, microgravity measurements, and vertical electrical sounding–VES). Microtremor method was conducted at 377 points in average in the investigation area to define fundamental period and empirical transfer function; after that in order to create basin model and to define the shallow subsurface geometry, microgravity measurements were carried out by using Scintrex CG-5. Also, MASW measurements were carried out in approximately 277 profiles and Schlumberger VES measurements were conducted at approximately 7 points in the investigation area. The existence of a linear relation between H/V peak period values obtained by microtremor measurements and ground thickness in the investigation area is also supported by geothermal drilling logs (depth of 600 m) with microgravity survey. Also, in some parts of the investigation area, it was observed that high S velocity (Vs) values affected H/V peak period values in sections of the ground close to the surface and there was an inversely correlated relation between this ground thickness and peak period values. This event occurring in shallow depths is supported by both VES sections and 2nd order vertical gravity derivative. As a result, depth of the engineering bedrock was obtained between 200 and 700 m and this unit was proposed as Bornova Melange for the investigation area in the scope of the works carried out. Also, it is observed that the area from ground to the engineering bedrock consists of four different layers which were defined by individual S velocities and densities. According to all results, characterictics of the shallow subsurface show that there is a high heterogeneity. Therefore, according to Eurocode8 (EC8 2004) regulations, soil characteristic of the Menemen plain and its vicinity are in the S1–S2 soil class.

Response of Buildings with Inclined First-Story Columns to Near-Fault Ground Motion

In this paper a simple model of a three story building with inclined first-story columns has presented. The stories are supposed to be rigid and are connected to axially rigid mass less columns by elasto-plastic rotational springs and linear rotational dampers. The considered model is subjected to horizontal component of fault normal pulse with different magnitudes and the governed nonlinear differential equations of motion have been solved by the forth order Runge-Kutta method. Results indicate that the inclination of the first-story columns stiffens the system. However, the change of the frequency of the first mode is small. The deformation of the first story with inclined columns is such that it forces the building in a pendulum-like motion. So it would be possible to reduce the relative building response. Results indicate that an optimum value of inclination angle of the first-story columns is . Under this condition the first-story drift decreases while upper-story drift increases, respect to the common building with . For larger inclination angles the gravity effect leads to increase the first-story drift as well. This solution would be useful in earthquake resistant design of buildings with architectural limitations at the first story.

Strength Reduction Factor (R) and Displacement Amplification Factor (Cd) of Confined Masonry Wall with Local Brick in Indonesia

Indonesian local brick in the masonry wall with a cement-based mortar has different physical and mechanical characteristics from the developed countries that are always used as references. Because of the different behavior with another countries and low strength of local brick, it requires a lot of research to get the strength reduction factor (R) and the displacement amplification factor (Cd). It is important in order that the design of earthquake resistant buildings in Indonesia more rational with the use of local brick. The study was conducted using cyclic loading with the appropriate protocol to simulate earthquake loads on the model structure that has been scaled. To increase the low performance of confined masonry wall, bamboo strips were used as reinforcement for some models. The study discussed the value of R and Cd towards the Indonesian and developed countries code. The results showed the mechanical characteristics of local brick masonry with cement-based mortar is different from developed countries. The basic differences are the strength and stiffness of the local brick lower than mortar as a binder. This results showed that utilizing equations R and Cd from developed countries needed further attention for local brick masonry in Indonesia.

RETRACTED ARTICLE: On the seismic performance of bamboo structure

While the earthquake resistant building design and construction code has been developed in sophisticated national/city level, the implementation at the local level has been more of an exception than the rule. Other than concrete and steel, one such material that can be used in construction in the seismic zone area of the developing countries like India, especially in the northeast states, is bamboo, where bamboo is available in abundant. Bamboo’s light weight and relative flexibility make it a particularly attractive alternative for residential construction in seismic regions. Compared on a mass-per-volume basis to concrete, steel and wood, bamboo is second to concrete for strength, and ranks first for stiffness. As strong as mild steel with the compression strength of concrete, amazingly, one inch of bamboo can hold up to 7 1/2 tons of weight. This present study is an attempt to implement bamboo construction in Manipur which is regarded as one of the most seismically active regions worldwide. In this work, a bamboo housing system and a reinforced concrete frame structural system was modeled using finite element analysis program SAP, considering the model structures to be taken from the types of building that is built in Manipur. A parametric study is conducted to investigate the seismic performance of the structures and El-Centro Earthquake and Kobe Earthquake recorded excitation are used for input in the dynamic analysis on the models. The study has revealed that the bamboo structures are performing better in earthquake than the commonly built RC residential building. The behavior of the bamboo structure modeled in this present study gives an opportunity to accept bamboo as a construction material in seismic zone areas.

Determination of Time Period of Vibration Effect on Seismic Performance of Building

Most seismic codes specify empirical formulas to obtain the fundamental period of buildings. The equations specified in present IS codes, are according to the available data on the time period of buildings measured from their recorded accelerograms. Shear-wall dominant reinforced concrete buildings, constructed, using codes specification are commonly built in different countries, facing a substantial seismic risk, in spite of their high resistance against ground motions. Current seismic code provisions including the Uniform Building Code (International Conference of Building Officials, Whittier, CA, 1997) and the Indian Seismic Code (Criteria for earthquake resistant design of buildings, fifth revision, 2002) are considered to evaluate the effect of time period on seismic behavior of building.In this study, time period obtained by code formulas are compared with those obtained by modal analysis in SAP2000. Also the top story displacement (as an adequate parameter of determination the seismic performance of building) correspond to the values of mentioned time period are estimated using uniform building code and software respectively. It is observed that current empirical equation for calculating the time period of RCC buildings is rather inaccurate. Also it is shown that the time period has very effective influence on seismic performance of building.

Loose Couplings

Rigid designs are often brittle under stress; loosely coupled systems, on the other hand, can withstand changing conditions and stresses more effectively. Such designs are often more adaptable. Currency exchange rates, information hiding, and the design of earthquake-resistant buildings all share this loose coupling property.

Hybrid Base Isolation System with Friction Sliders and Viscous Dampers in Parallel: Comparative Dynamic Nonlinear Analysis with Traditional Fixed Base Structure

In the present paper we have analyzed a multi-storey reinforced concrete (RC) building in presence of a hybrid seismic protection system for highlighting the limits of the conventional fixed base seismic design of structures. This hybrid seismic protection system is a passive structural control system that combines the Base Isolation System (BIS) and the Passive Supplemental Damping (PSD). The Viscous Dampers (VS) and Friction Sliders (FS) are the devices adopted in parallel for realizing the innovative base isolation system. The fixed base structure and the base isolated structure have been designed and verified according to the European seismic code EC8 and the European code for the design of concrete structures EC2. A three-dimensional dynamic nonlinear analysis for a base isolated structure has been performed adopting recorded accelerograms for the defined bi-directional ground motions according to the conditions imposed by EC8. The seismic isolation is a promising alternative for the earthquake resistant design of buildings and its peculiarity is that the base isolated buildings are designed such that the superstructure remains elastic and the nonlinearities are localized at the isolation level. In this paper a comparative analysis is presented between the base isolated structure, with the viscous dampers in parallel with friction sliders, and the traditional fixed-base structure.

Kisah Sukses Inovasi Marketing from Commodity Becomes Solution (Studi Kasus Tentang PT Holcim Indonesia Tbk)

Cement is a strategic commodity. Indonesia as a developing country continues, cement becomes something absolute. Particularly, in the next few years, infrastructure development continues announced. To it, we need to anticipate the occurrence of scarcity (shortage) of cement to meet the needs in the country in the next couple years. Fears of a shortage of cement in the country are quite groundless. Currently installed production capacity of the national cement industry around 47.5 million tons per year, spreads over nine locations in Indonesia. Meanwhile, the average utilization rate of production capacity cement plant reaches between 80% -85% or about 38-40 million per year. Meanwhile, the current level of cement consumption reached about 33 million tons (still a surplus of about 5-7 million tons). The problem is, if the shortage is met from imports, it could damage the domestic cement industry. Therefore, to meet the interests of industry and consumers, the best way is the expansion of the new plant. And to support the expansion of the factory in the country, clearly requires a major investment. Based on the assumptions above, Holcim as a newbie in the national cement market, which previously bought cement Cibinong also takes part in the national market. Now, Holcim is not half-hearted continuously expanding its new factory in Tuban to increase the strength of its two plants that are already running. A series of innovations in marketing activities are carried out, ie not just treating cement as a commodity but rather providing a range of service solutions to users via the outlet solution that provides aid earthquake resistant building design, material supply multi-brand, as well as a series of cooperation in the process of financing by establishing cooperation to the bank.