Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

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).

Projects with seismic isolation are increasing in Peru, even the Peruvian Seismic Standard establishes that seismic isolators must be used in hospitals located in seismic zones 4 and 3 of the Peruvian seismic map. It is also accepted that there may be isolated buildings on floors S0, S1, S2 and S3. In isolated buildings that are in soil type S3 and seismic zone 4, maximum displacement values ​​are obtained. This involves the use of flexible connections, plus in some cases these offsets result in a smaller usable area of ​​the building. An alternative to reduce these displacements is the use of supplemental viscous dampers at the base of the isolated building, which adds damping to the isolation system. In this investigation, 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 supplemental viscous dampers, considering 5 different damping percentage conditions: 15%, 30%, 45%, 60% and 75%. For all analyses, 7 time history records compatible with Peruvian seismicity were used. Isolated base displacement reductions will be acquired up to 30% of their starting value. The variation of the responses (accelerations, deviations, shear forces and dissipated energy) was analyzed as a function of the increase in damping. It was verified that the Peruvian seismic combination of isolators and dampers tends to increase the responses of the superstructure.

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.

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.

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 floors, 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.

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.

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.

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.

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.

The author proposed a new seismic response control system using a block and tackle (hereinafter, referred to as a dynamic pulley damper system) developed especially for the high-rise buildings. The proposed system has a configuration where a damper is installed on the track of the cable-stayed wire, amplifying the amount of movement of the wire by using a movable pulley that increases the damping effect to reduce the vibration of a building. we apply this system to connect the core structure (parking tower) and the surrounding frame (housing part) of a high-rise building. This system aims to reduce the earthquake response of the building by the force of the damper attached to the core structure. To verify the effectiveness of this response control system, two types of shaking table tests were conducted; one is the large-scale shaking table test using a magnetic damper, an-other one is the small-scale shaking table test using a steel damper. The mathematical model of the dynamic pulley damper system to implement the frame analysis was developed and the results of simulation analysis are compared with the experiments.