Scielo RSS http://www.scielo.org.pe/rss.php?pid=2309-041320190002&lang=es vol. 29 num. 2 lang. es http://www.scielo.org.pe/img/en/fbpelogp.gif http://www.scielo.org.pe http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200001&lng=es&nrm=iso&tlng=es For 30 years the Structural Laboratory of the Peru Japan Center for Earthquake Engineering Research and Disaster Mitigation (CISMID) from the Faculty of Civil Engineering (FIC) of the National University of Engineering (UNI) is been testing different types of structural system, mainly confined masonry walls. In that sense, large number of experiments have been conducted in confined masonry walls. Analytical model for capacity curve is presented for walls with different types of masonry units, such as industrial hollow bricks, solid handmade bricks and tubular bricks which are the most representative units in Metropolitan Lima and Callao. Tetra-linear models are calibrated with experimental results in order to provided generalized model in terms of sensitive parameters which determines the capacity curve for flexural shear failure mechanism, such as longitudinal and transversal steel ratio, slenderness ratio and axial load ratio where shear stress is observed in the cracking, yielding, maximum and ultimate points. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200002&lng=es&nrm=iso&tlng=es The author proposed a new seismic response control system using a block and tackle (hereinafter, referred to as a dynamicpulley damper system) developed especially for the high-rise buildings. The proposed system has a configuration where adamper is installed on the track of the cable-stayed wire, amplifying the amount of movement of the wire by using a movablepulley that increases the damping effect to reduce the vibration of a building. we apply this system to connect the corestructure (parking tower) and the surrounding frame (housing part) of a high-rise building. This system aims to reduce theearthquake response of the building by the force of the damper attached to the core structure. To verify the effectivenessof this response control system, two types of shaking table tests were conducted; one is the large-scale shaking table testusing a magnetic damper, an-other one is the small-scale shaking table test using a steel damper. The mathematical modelof the dynamic pulley damper system to implement the frame analysis was developed and the results of simulation analysisare compared with the experiments. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200003&lng=es&nrm=iso&tlng=es The construction of isolated structures is increasing in recent decades in seismic countries. In Peru, the national regulation indicates that important buildings such as hospitals located in areas of high seismic risk must incorporate isolation systems to reduce structural and nonstructural loss. These systems protect the main structure from the effects of a seismic event by separating its base from the earth movement and by reducing the relative displacements and accelerations between adjacent stories. In the structural design process of buildings and seismic protection systems, having numerical models that properly represent the real behavior of the buildings is of high importance. In this context, experimental modal tests represents an attractive cost-effective non-destructive tool to obtain an accurate characterization of the experimental structural response. This paper presents the experimental tests carried out in a base-isolated educational building built in 2014 that has seven stories and three basements with a total built area of around 7500 m2. Data acquisition was accomplished with autonomous units (acquisition system and transducers incorporated in a single unit) whose versatility allowed measuring a significant number of degrees of freedom in a limited amount of time. The dynamic properties experimentally identified were used to calibrate the finite element model of the building. The results showed that the design model approximates correctly to the experimentally identified ambient vibration response when considering rigid supporting conditions as well as the interaction of partitioning elements such as walls and parapets. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200004&lng=es&nrm=iso&tlng=es Dry stone retaining walls, DSRW, are low-cost traditional structures made of stones aimed to stabilize, support backfill and avoid soil erosion. They have massively been used as foundation of dwellings by vulnerable population located in the steeped hills surrounding some Latin-American cities. These walls are built following ancient techniques that are neither well studied nor formally established. Millions of people live in these conditions in seismic zones generating a high-risk situation. Experimental and numerical studies are needed in order to evaluate the reliability of low-cost DSRW and to validate or improve traditional techniques. The objective of this ongoing research is to design and construct a full-scale testing equipment to assess DSRW performance against lateral out-of-plane seismic forces. The methodology consists in the following steps: (1) Review of state-of-art of experimental testing of DSRW, (2) Analysis of failure modes of similar constructions (3) Conceptual and structural design of optimum full-scale testing equipment, (4) Construction planning (blueprints and budget) and (5) Construction and operation. Testing equipment found in technical literature can be classified into two groups according to the applied force: dynamic and static. Forces in dynamic tests are the result of acceleration imposed to the specimen, e.g. shaking tables and centrifuge machines. Forces in static testing are applied by hydrostatic pressure, lateral earth pressure, and specimen´s weight. Applied forces in dynamic tests simulate seismic forces well. On the other hand, it is a high cost solution and requires very specialized staff for operation and maintenance. Static alternatives are more affordable but seismic forces are roughly simulated by static forces. In this work a tilt table is proposed to test full-scale specimens. In this test, the specimen is built in a horizontal table that is slowly rotated. In this way, a static out-of-plane force acts in each particle of the specimen. The magnitude of the total force is the specimen´s weight multiplied by the sin of the rotating angle. Static test results could be conservative but they could give a good approach to understand DSRW damage accumulation process and failure. Two equipments were proposed: (1) tilting table for monotonic static test and (2) tilting table for cylic test. We compare costs, required area, construction feasibility, and operation manageability. We conclude that both of them are straightforward solutions to assess DSRW performance against out-of-plane lateral forces. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200005&lng=es&nrm=iso&tlng=es The behavior of the composite steel deck is conditioned, mainly, to the interaction that exists between the concrete and the steel deck, the shear connection between these two materials is provided by the mechanical adherence, which exists in its interface. In order to study these characteristics, a series of full-scale slab tests have been carried out, such as bending tests to identify the slipping load, which is directly related to the shear bond strength of the slab. The study of the shear bond strength is very important because in most cases the geometric conditions of the section and the slenderness of the slab will lead to this type of failure. For this reason, this research will be in charge of studying this failure condition, based on previously full-scale slab tests and newly constructed specimens, in order to cover as many situations as possible. The experimental results of these tests, such as the slipping load and the corresponding deflection, will allow establishing a new relationship between the slipping load, the geometric and mechanical parameters. This proposed relationship will be carried out for each of the steel deck profiles under study and this formulation will be validated as an alternative proposal to the "m y k method". http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200006&lng=es&nrm=iso&tlng=es Masonry structures constitute a large proportion of the building inventory in Lima and in most cities in Peru, mainly because of their benefits in terms of low cost, good mechanical properties and easily worked. It was observed in the cyclic loading test of clay masonry walls carried out at the Structural Laboratory of the Japan-Peru Center for Earthquake Engineering Research and Disaster Mitigation (CISMID) that the modes of failures can be mainly generated by shear forces. Based on the previous information, it is known that diagonal cracking and slip of the mortar-brick joints are the dominant failure mechanisms of confined masonry walls. In order to determine the mechanical behavior in the mortar-brick joint, an experimental program was carried out, by using industrial and handmade clay bricks. The test specimens were specifically designed to transmit pure shear along the bed joints under certain constant levels of compressive stress normal to the bed joint. The results of experimental shear tests are presented and discussed. It is then found a consistency between the behavior of masonry joints under shear with the Mohr Coulomb criterion. The shear failure capacity was influenced by the brick type, pre-compression load level and mortar type. It is also noticed in this experimental study that the pre-compressive stress normal to the bed joints significantly increase the shear strength of the mortar-brick joint. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200007&lng=es&nrm=iso&tlng=es In order to protect buildings against earthquakes that are categorized as "common" according to the Peruvian Earthquake Resistant Standard, a prototype of Recycled Rubber Seismic Isolator ("RRSI") was developed in the structural laboratory of the Japan-Peru Center for Earthquake Engineering Research and Disaster Mitigation - CISMID, Peru. The raw material used to manufacture this device was recycled rubber tires; the rubber tire was cut into square shape sheets with 190mmx190mm of cross-section and a total thickness of around 11 mm. Rubber tire sheets were joined to each other by a vulcanization process, including rubber layers with 3mm of thickness made of recycled rubber tire powder in between rubber tire sheets; and in between the rubber tire sheet and the steel plate at both ends of the bearing. Two specimens were tested in a shaking table under a free vibration impulse or displacement in order to get their natural vibration frequency, natural period, and inherent damping. Then, to obtain the hysteretical behavior, a cyclic lateral reversal-loading test was conducted on three different specimens applying a constant axial load of 330MPa, 270MPa, and 220MPa respectively and a lateral displacement pattern with different levels of shear deformations up to the failure, which occurs at a shear strain of around 100%. From the experimental results, a nonlinear hysteretic behavior and energy dissipation were observed, decoupling the lateral movement. Finally, a numerical model was proposed to model the nonlinear hysteretic behavior of the RRSI based on a Modified Bouc-Wen model. This numerical model was simulated by using the specimens as base isolators for buildings. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200008&lng=es&nrm=iso&tlng=es Projects with seismic isolation are increasing at Peru, even the Peruvian Seismic Standard establishes that seismic isolators must be used in hospitals located in seismic zone 4 and 3 of Peruvian seismic map. Is also accepted that there may be isolated buildings on soils S0, S1, S2 and S3. In isolated buildings that are on soil type S3 and in seismic zone 4, maximum displacement values are obtained. This implies the use of flexible connections; in addition in some cases these displacements cause that there is a smaller usable area of the building. One alternative to reduce these displacements is the use of Supplementary Viscous Dampers in the base of isolated building which adds damping to isolation system. In this research, a mathematical model of a 5-story building with elastomeric isolators, located in seismic zone 4 and soil type S3 was evaluated. This model was then analyzed with Supplementary Viscous Dampers, considering 5 different conditions of critical damping ratio: 15%, 30%, 45%, 60% and 75%. For all analyzes, 7 time-history records compatible with Peruvian seismicity were used. Displacement reductions of isolated base were obtained up to 30% of its initial value. The variation of responses (Accelerations, Drifts, Shear Forces, and Dissipated Energy) was analyzed as a function of the damping increasing. It was verified that the Peruvian seismicity combination of isolators and dampers tends to increase the responses of the superstructure. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200009&lng=es&nrm=iso&tlng=es This paper initially describes aspects of the modeling of structures equipped with energy dissipators Shear Link Bozzo (SLB) and develops two iterative design procedures to select these devices. This methodology is applied to a precast 5-story reinforced concrete building. The SLB energy dissipation devices are initially stiff, but ductile with a range of yielding forces from 36 kN to 900 kN characterized by 52 + 52 standard devices. Moreover, these devices can be combined in parallel giving a very wide range of possibilities for selection and corresponding structural response. Therefore, to simplify its automatic selection, this article presents two procedures: (1) direct iteration and (2) inverse or fixed force iteration. Both procedures were implemented in an automatic application or "plugin" for the ETABS program that automates its selection for a specific structural system or architectural configuration of these elements. Using these devices, the energy introduced by an earthquake into the structure can be dissipated, protecting other structural elements that suffer damage. The SLB energy dissipation devices are affordable to get a significant performance improvement in the overall structural response. This work presents a five-story precast reinforced concrete building frame, called SLB Building, that provides 4 departments per level all with a diaphanous interior floor. The building is made up of 11 columns with a constant 40x40cm section and all its beams have hinges at the ends. This building was equipped with 120 small SLB devices showing its performance for the maximum earthquake of Peruvian seismic code without ductility reduction (R = 1) by means of nonlinear time history with ten seismic records compatible with the S1 soil spectrum. In this structure, all seismic energy dissipation was concentrated in these devices so there would be no structural damage. In addition, the levels of non-structural damage were controlled with initial stiffness of these devices since lateral displacements were reduced to levels below the Peruvian seismic code (or even immediate occupancy for devices greater than those provided in this example). At the same time, the levels of acceleration decrease in height to only 0.3g and the base shear coefficient is reduced from almost 1.2 to only 0.12-0.2 (this means an R factor between 6 and 10 without structural damage). http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200010&lng=es&nrm=iso&tlng=es The site response analyzes provide an idea of the behavior of soils under seismic loads, involving a large number of variables that determine the non-linear behavior of the soil. Due to the complexity of these analyzes, in practice the effects of nonlinear soil behavior are incorporated as factors that modify the seismic response spectrum in rock (linear behavior). In this study, nonlinear site response analysis has been performed for 50 soil profiles in an attempt for covering a wide range of shear wave velocity profiles using the software DEEPSOIL V.7. For this purpose, 03 seismic records have been spectrally adjusted to uniform hazard spectrum of 475, 1000 and 2475 years of return period of a reference soil profile with Vs30 of 760 m/s. Subsequently, a comparison of the results obtained from the site response analysis with the parameters stipulated in the Peruvian Seismic Design Code E.030 (2018) for the design spectrum was made, in order to evaluate if the last one adequately matches the response of each type of soil. Discrepancies in the ranges of Vs30 values that this standard considers for the classification of soils and the factors that determine the width of the platform of the design spectrum have been found, implying that a new range of Vs30 for the soil classification is needed. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200011&lng=es&nrm=iso&tlng=es Currently, it is assumed that seismic force applied to the building acts independently in two or three principal directions, orthogonal to each other, this assumption is not necessarily correct, because seismic analysis of buildings should consider the bidirectional effects of an earthquake. This consideration takes place if an angle of real incidence and the seismic force acting in each orthogonal direction is taken into account to estimate the maximum response of the building. These effects will be analyzed by using the linear time-history analysis of 11 structures with different rigidities and eccentricities in two orthogonal directions, using angles of incidence each 10 degree and 20 Peruvian seismic records for rigid, intermediate and flexible soils obtained from database of Japan-Peru Center for Earthquake Engineering Research and Disaster Mitigation (CISMID) and Geophysical Institute of Peru (IGP). Furthermore, a non-linear time-history analysis will be carried out, which will be applied to one of the 11 structures and will use angles of incidence each 10 degree and one seismic record. The maximum seismic response will be compared with the maximum modal response spectral analysis obtaining a linear equation. to obtain a propose based on amplification factors. Finally, amplification factors are proposed to obtain a relationship between modal spectral analysis and time-history analysis that consider the effects of the bidirectionality and the angle of incidence in reinforced concrete structures. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200012&lng=es&nrm=iso&tlng=es In 1746, Lima Region was hit by a severe earthquake and a consecutive tsunami in Callao City caused 96% of casualties in the Callao City population. Under SATREPS Project [1], several studies were realized, and they concluded that a severe earthquake (Mw8.6~8.9) may occur in Lima City [2], following by tsunami which may hit a large coastal area. In that sense, harmful scenarios can occur. Based on last studies, and historical earthquake consequences in Callao City; Local government in La Punta, the most tsunami prone district in Callao, has designated 19 reinforced concrete (RC) buildings as tsunami shelters. Nevertheless, the lack of the structural vulnerability studies of these buildings in front of an earthquake and consecutive tsunami scenario, makes uncertain the good performance of the buildings. Guidelines of other countries such as Japan, The United States and Chile, are oriented to calculate the tsunami forces; nevertheless, these guidelines lack information about structural performance of buildings in front of earthquake-tsunami scenarios. This paper describes a methodology to assess the sequential action of the earthquake and the consecutive tsunami to evaluate the structural performance and the damage level to ensure the safety of buildings and their inhabitants. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200013&lng=es&nrm=iso&tlng=es Structures in chemical and petrochemical facilities are often located in areas that may be subjected to blast loading. Occupied buildings typically have non-structural components located along the interior of the exterior walls and roof such as windows, doors, wall mounted AC units, lights, furniture, storage racks, hanging equipment, and loose articles. Occupants of buildings subjected to accidental explosions may be injured from glass fragments and interior non-structural items becoming projectiles and impacting building occupants. As a pressure wave from a blast impacts the exterior of a building, the wall and roof components are rapidly accelerated inward. Equipment or contents mounted on or in contact with the exterior façade are also accelerated and may be dislodged and projected as debris. Items anchored to the ceiling structure can be thrown vertically from the initial forward deflection of the supporting member or break free from their supports and become falling debris hazards. Therefore, evaluation and mitigation of non-structural debris for buildings subjected to blast load is important to further mitigate the potential hazards to personnel occupying these buildings. This paper provides design retrofit recommendations based on accident investigation experience at chemical and refining facilities and engineered solutions for typical hazards commonly observed at these facilities. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200014&lng=es&nrm=iso&tlng=es Non engineering dwellings represents 83% of the stock of housing in emerging areas of Lima city. These dwellings are build with non-appropriated masonry bricks with walls that limits don´t meet the displacement control of the earthquake design standards NTE-030 and NTE-070. Considering the database of structural test of 33 years of experimental studies of the Structural Laboratory of CISMID, typical behavior curves are studied in order to propose damage limit state for masonry walls: build with industrial bricks, build with handmade bricks and build with horizontal hollow tubular bricks. Also, results of full-scale test on masonry house performed in the laboratory are studied. Ranges of inelastic development limit states of walls are proposed from the test results of full-scale test of the three types of masonry. Big difference in the capacity of walls with tubular bricks in comparison with the others types are found. Also limit drift values threshold are propose to be use in the analytical modelling of wall structures with handmade or tubular bricks. These proposal limits are smaller than the limit of NTE-030 standard. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200015&lng=es&nrm=iso&tlng=es This article reports the state-of-the-art of the implementation of finite element modeling for clay masonry walls under lateral loads. Important work had been developed at CIMID Laboratory of Structures in clay walls under lateral loads and, according to the review, nowadays, researches mainly report experimental tests with their numerical nonlinear models. This process is important to validate and complement their results. Bench-mark model developed in 1994 at Chiba University had been selected to evaluate all work developed at CISMID in these recently years. The evaluation uses three variables: 1) The study evaluated include experimental results for masonry walls, (2) The study evaluated use nonlinear models for interaction between mortar and bricks, and (3) The study evaluated record their results with graphics showing the failure process. Finally, evaluate these models with finite elements demand high costs because the hardware and software requirements. However, the acquisition of a computer for High Performance Computing is necessary to afford this kind of research. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200016&lng=es&nrm=iso&tlng=es Development of Fragility functions are a widely used tool to estimate the vulnerability through the probability of response damage occurrence of a structure at different seismic demand. These functions are very useful for researchers, engineers, insurance companies, territorial planning planners and decision-makers. The aim of this research is to develop a methodology to estimate the vulnerability of theses confined masonry dwelling through the fragility function. An experimental database of confined masonry wall of two kind of informal brick and statistical database were used. This research present typologies of a dwelling according to the type of material, number of story, and wall density respectively which are based on a statistical database. Besides, it describes a methodology to find the fragility functions based on experimental data tests that replicate the behavior of confined masonry walls and thus find the probability of the damage caused in this type of dwellings that exist in a great majority of the city of Metropolitan Lima and Callao. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200017&lng=es&nrm=iso&tlng=es Assessment of old factory infrastructure is required in order to keep them working especially after natural hazard event such as earthquake, tornados, or variation of gravity loads. This type of structure is considered essential since it should be safety for workers during operation time and to avoid possible economical losses if this facility stops its operations after any main seismic event. It is presented the structural assessment of the infrastructure of a melt shop facility, which it used for production of structural steel shapes. This infrastructure was built at the beginning of 80’s and it is located at near Pisco city in Peru. Reinforced concrete C columns and L beams make the frames of the structure and the rood is made by steel trusts. NDT and destructive tests were made for the reinforced concrete members as well of extraction of steel coupons from the roof trusts. Auscultation of foundation, reinforced concrete and steel structures were performed. It was found that several columns present damages such as spalling of cover, impact hits from heavy vehicles, which get in the interior of the facility. The roof presents metallic dust which was accumulated by the smelter operation. Heat of 50 Celsius degrees is the average temperature during the 20hours per day of operation time. Besides, capacity of several reinforced concrete columns and beams, and steel members of the roof is minor that their demands respectively according to Peru and international codes. The performance of the full structure of the melt shop including concrete and steel structures presents allowed drifts according seismic provisions, however this structure behaves on its nonlinear range under demands of Peru seismic code. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200018&lng=es&nrm=iso&tlng=es This paper presents a procedure for the fragility assessment of structures subjected to earthquake and tsunami loads, by using the inelastic displacement accumulation as a measure of damage. The proposed methodology considers a non-linear static analysis (pushover) for the earthquake case, and a non-linear static load for the tsunami case, taking as a starting point the final condition of the structure after the occurrence of an earthquake. However, since the impulse force is the critical component of the tsunami load, a simplified approach in terms of the flow depth is used to estimate the total tsunami load. By combining the earthquake effect with the tsunami hazard, a function relating the earthquake spectral acceleration, the tsunami flow depth and the lateral drift is obtained. Finally, a case study of the typical timber structures located in the municipality of San Andrés de Tumaco, at the Colombian Pacific Coast, is analyzed in order to assess de proposed methodology. The fragility curves obtained allows to determine a new approach to the Multi-hazard risk assessment in areas prone to the occurrence of earthquakes and tsunamis. http://www.scielo.org.pe/scielo.php?script=sci_arttext&pid=S2309-04132019000200019&lng=es&nrm=iso&tlng=es Along the history, Peru have suffered many human and material losses due to the effects of natural hazards, particularly earthquakes, only in the capital city, Lima, three large earthquakes have occurred in the last century, in 1940, 1966 and 1974. But hazards itselves would not become disasters without a vulnerable population, which is the case of Peru, where the growing and developing of cities has lacked of any planification and it has been disordered, with people building without following the current regulatory framework that ensures good structural behavior during a severe seismic event. For those reasons, among others, is needed a tool that permits the identification of highly risk areas in case of earthquakes. The current study proposes an automated system on a GIS platform that allows to estimate the damage effects of earthquakes in buildings, showing the results as repairing costs. Using as basis Geotechnical information like peak ground acceleration (PGA) or Spectral acceleration (Sa), urban cadaster information (material of the building, the soil, the number of stories, etc.) and using the outputs of experimental tests and analytic simulations for different building types used in Peruvian territory, like masonry buildings, reinforced concrete buildings, adobe or quincha buildings, wooden buildings among others. This tool would allow stakeholders to have an idea of the expected damage for the next quake and would help them to take actions before the event, actions like retrofitting or relocating buildings.