PDF superior Seismic behavior of Mudejar structures

Seismic behavior of Mudejar structures

Seismic behavior of Mudejar structures

There are two main theories that make possible the analysis of this type of constructive ele- ments. First, the micro-models have their field of application in the study of the local behaviour of masonry structural details. They are used for example to study the behaviour of the interface or behaviour at specific points such as doors or windows. Moreover macro-models are used when the structure is formed by solid walls with sufficiently large dimensions that make the stresses across and along the elements substantially uniform. This is our case so an analysis us- ing macro-models theories is made (López et al, 1998; Lourenço, 1995; Pérez, 2006). Accord- ing to the results obtained using the theories developed by different authors, the evaluation of the elements of stone masonry and brick walls that have been characterized by the following values:
Mostrar más

10 Lee mas

Vol. 69 Núm. 285 (2018): Hormigón y Acero

Vol. 69 Núm. 285 (2018): Hormigón y Acero

To minimize or prevent structural torsion of RNC-isolated structures, the RNC isolator has inherently independent bearing and pre-yield elastic stiffness mechanisms to allow for accu- rate and proper tuning of its elastic stiffness as required with no influence on its bearing mechanism nor on the resulting overall dimensions and behavior of the RNC isolator unit. To prevent seismic pounding of RNC-isolated asymmetric superstructure, the RNC isolator has an inherent self-stopping or buffer mecha- nism, which is able to draw down all the possible pounding of the superstructure downward to be inside the solid body of the RNC isolator. This buffer mechanism is activated if the peak bearing displacement exceeds a certain design displacement previously selected by the structural designer. For more information on the RNC isolator please refer to the above references by the authors. All studies are carried out using nonlinear time history analysis provided by the specialized computer code SAP2000 ([58]), as explained in details by [59]. It is to be emphasized that possible frictional pounding of asymmetric buildings with their closely spaced adjacent structures is not considered in this study. The reason is that the proposed methodology for minimizing or even eliminating torsion aims at forcing the asymmetric building to nearly behave as a symmetric building exhibiting no twist around a vertical axis, which is the only source of frictional pounding. Accordingly, the likely frictional pounding is assumed negligi- ble until achieving the objectives of this paper without negatively influencing its scope.
Mostrar más

103 Lee mas

Influence of axial load in the seismic behavior of reinforced concrete walls with nonseismic detailing

Influence of axial load in the seismic behavior of reinforced concrete walls with nonseismic detailing

earthquake, one of the strongest ever measured (EERI, 2010). This earthquake impacted 500 km of Chilean coast and over 12 million people (about 72% of the country‟s population) experienced a Mercalli intensity of VII or stronger. A tsunami was triggered after the earthquake, which devastated several towns near the coast. Serious damage was imparted to residential and industrial buildings, highways, railroads, ports and airports. More than 80,000 residences were destroyed and more than 100,000 had substantial damage caused by the earthquake and the tsunami. The performance of tall reinforced concrete (RC) wall buildings with 9 or more stories was acceptable; about 2% of the newer building inventory presented severe damage (Jünemann et al., 2012; Massone et al., 2012) and only one of these buildings collapsed. Damage in this type of structures was most likely attributed to poor concrete confinement, inadequate boundary reinforcement detailing, and high axial loads (Jünemann et al., 2012; Wallace et al., 2012). This research is aimed to study the third factor; how the level of axial load affects the seismic performance of RC walls.
Mostrar más

108 Lee mas

Optimal passive control of nonlinear asymmetric structures : a performance based design

Optimal passive control of nonlinear asymmetric structures : a performance based design

Tuned Mass Dampers (TMD) have extensively been used to successfully mitigate narrow bandwidth type loads of linear mechanical systems based on an optimal tuning frequency. Nevertheless their effectiveness to control structural systems subjected to broad bandwidth seismic type loads is still dubious, mainly because these structures are particularly designed to withstand nonlinear behavior which presumes a mistuning effect of the structure-TMD system. There are some solutions that have been developed to counteract this condition, modifying the passiveness of the TMD to an active condition by adding supplemental control devices. This investigation presents an effective and optimal solution to keep the passiveness of the system. Previous investigations have identified that a large damper-structure mass ratio is more effective when the nonlinearity of the structure is considered, and the optimum way to deal with this condition is by sub-structuring the system subtracting the TMD mass from the structure itself. A simple way to achieve this concept is by optimally isolating the roof of the structure. The optimum parameters of this flexible interface such as the damping ratio and the tuning frequency are studied conceptually through two stages. The former is focused on nonlinear single Degree of Freedom (SDOF) systems. The latter is extended to nonlinear coupled 2-DOF systems in order to consider the torsional condition. Results show that large TMDs are a robust solution to enhance the seismic performance of nonlinear structures achieving not only the torsional balance condition by reducing deformations and annihilating the torsional response but also attenuating structural damage.
Mostrar más

116 Lee mas

Influence of the mechanical properties of friction dampers on the seismic response of steel frame structures

Influence of the mechanical properties of friction dampers on the seismic response of steel frame structures

Conventional seismic design codes allow for structures to be designed in such a way that the forces induced during strong earthquakes may exceed the elastic capacity of the building. This inelastic behavior is the mechanism through which typical constructions dissipate energy, and although it achieves the principal objective of avoiding collapse, it can ultimately lead to heavy structural damage that may be as expensive to repair as to replace a collapsed structure (Pall and Marsh, 1982). Two of the preferred lateral force resisting configurations for steel frames are the moment-resisting frames (MRF) and the braced moment-resisting (BMR) frames (Pall and Marsh, 1982). Damage observed in the 1994 Northridge earthquake (M w = 6.7), however, questioned the ability of these types of
Mostrar más

105 Lee mas

Aislamiento sísmico de estructuras, parte II: un caso práctico con el aislador RNC

Aislamiento sísmico de estructuras, parte II: un caso práctico con el aislador RNC

This paper is the second of two companion papers. It intro- duces the seismic isolation concept and addresses the possibility of nearly eliminating, or at least minimizing, the torsional responses of isolated asymmetric structures using the Roll- in-Cage (RNC) isolator considering near-fault (NF) ground motions. Then, the outcome of this study is employed into fur- ther study on the ability of the RNC isolator to partially and entirely eliminate torsional seismic pounding of isolated asym- metric structures with their closely-space surrounding adjacent structures under the same severe NF ground motions, which are rich of displacement and velocity pulses. To minimize tor- sional responses, the RNC isolator has an inherently independent bearing and pre-yield stiffness mechanisms. Therefore, the RNC isolators are arranged into four sets with unequal pre-yield elas- tic stiffness underneath the asymmetric structure. Such different elastic stiffness are accurately tuned to shift the isolators’ center of rigidity at the isolation level to coincide with the structural center of mass above the isolation level. To prevent direct seismic pounding of the RNC-isolated superstructure with its closely- spaced adjacent structures, the RNC isolator is provided with an inherent self-stopping (buffer) mechanism to limit the peak lateral bearing displacement and consequently the peak lateral structural displacement to a preset design value by the designer, which is particularly useful in case of having insufficient or limited seismic separation gaps between adjacent structures. 2. Dynamic behavior improvement of RNC-isolated asymmetric structures
Mostrar más

19 Lee mas

Régimen tributario del reino mudejar de Granada

Régimen tributario del reino mudejar de Granada

diezmo di.z que por su ley eran obligados a pagar a los dichos reyes moros, como el diezmo de pan e panizo e otras cosas que cogían de sus heredades, e que agora por entrar como entra la[r]

26 Lee mas

Transient behavior of a system composed of conductive thin wire structures excited by harmonic and lightning type signals

Transient behavior of a system composed of conductive thin wire structures excited by harmonic and lightning type signals

The numerical code used is based upon the Moment Method as studied by Harrington [10], and can be applied to any electrode configuration composed of thin wires with any number of signal injection points working si- multaneously [11]. Thus, it is possible to study the effect on the ground caused by the excitation of two buried electrodes of any shape and interconnected by an external conducting wire or, as in this work, the potential in- duced in the isolated passive electrodes of the system while only one of them is activated [12]-[14].

17 Lee mas

EL PAPEL DE LA ACADEMIA CON LA GESTIÓN DEL RIESGO: LOS RESULTADOS DE LA CORPORACIÓN UNIVERSITARIA DEL META EN EL TEMA DE LA AMENAZA SÍSMICA DURANTE EL LAPSO 2006 - 2012

EL PAPEL DE LA ACADEMIA CON LA GESTIÓN DEL RIESGO: LOS RESULTADOS DE LA CORPORACIÓN UNIVERSITARIA DEL META EN EL TEMA DE LA AMENAZA SÍSMICA DURANTE EL LAPSO 2006 - 2012

Since the middle of the first decade of the 21st century the University Corporation of Meta has gradually assumed as top institution leadership at the regional level of the subject of the seismic threat not only of llanero foothills but also of the Colombian Caribbean platform. In Colombia is counted the number of universities that have contributed to research on this topic. Deal with issue by an institution of higher education, demand that a research group attached to it not only to strive to develop research on the scientific aspects pertaining to this type of threat. The results of it entails to unravel mysteries about the threat and therefore understand it better to take the right measures that lead to mitigate its effects. The results of the research the research group "Studies on seismic risk and the llanero foothills natural threats" have achieved great progress in terms of compression of the phenomenon for both scenarios, not only with regard to the origin of this knowledge, but also with respect to measures to take in each case to mitigate their effects. Is for this reason that it is also an obligation to disseminate these results to society in General not only the specialized scientific community
Mostrar más

7 Lee mas

Novel linker to bioconjugation based on tetrahydrothiadiazine-2-thione (thtt) scaffold

Novel linker to bioconjugation based on tetrahydrothiadiazine-2-thione (thtt) scaffold

On the other hand, Kadcyla™ (Trastuzumab emtansine) is an innovative, unique, and selective antineoplastic drug used in patients with advanced breast cancer (HER2+). This ADC is composed of the antiHER2 antibody trastuzumab (Herceptin®) and the cytotoxic microtub ules agent, DM1, bound through a bifunctional succinimidyl 4-(N-maleimidomethyl) cyclohexa ne- 1-carboxylate (SMCC) as a non-cleavable linker. This drug acts selectively on HER2 + tumors cells, exercising, on one hand, the mechanisms of action of the trastuzumab, and on the other hand, the powerful cytotoxic effect of DM1 (Figure 13B). The main advantage of this ADC is that it has a selective release, allowed to minimize its side effects in comparison to other agents for the same pathology. 71, 76
Mostrar más

65 Lee mas

Geometrical characterization of undisturbed soil samples using X-ray computed tomography image analysis. Effect of soil management on soil structure

Geometrical characterization of undisturbed soil samples using X-ray computed tomography image analysis. Effect of soil management on soil structure

the box-counting dimension of the pore space of tilled and undisturbed soils [Chun et al., 2008; Gantzer and Anderson, 2002; Kravchenko et al., 2011]. Let us note here that N soil samples have lower N F D and higher V F D than T samples. Moreover, the boundary surface of the pore space of the N samples also seems to have greater complexity, because of its roughness. In contrast with fractal parameter N F D , parameters V F D and SF D do not show any trend with depth. Probably, this is due to fact that samples correspond to a narrow layer of the uppermost part of the soil. Similar results were reported by Perret et al. [2003]. San José Martínez et al. [2010] used multifractal analysis of the variation of cross-sectional porosity with depth of CT images of large soil columns to characterize the porosity spatial memory. They found that the Hurst exponent of this series is congruent with persistence or positive autocor- relation. Thus, the persistence of sectional porosity could explain the absence of any trend of fractal parameters V F D and SF D with depth. The dierent behavior that parameters N F D show suggests the lack of a direct relationship between pore space structure and pore size distribution (dierent pore size dis- tributions seem to yield pore space geometries that appear indistinguishable in this type of soils).
Mostrar más

266 Lee mas

A displacement-based seismic design method for framed structures involving sidesway-collapse prevention

A displacement-based seismic design method for framed structures involving sidesway-collapse prevention

Asimakopoulos et al. (2007) developed an equation to calculate a yield displacement amplification factor as a function of the design ductility and the stability coefficient to consider second order effects for design of steel moment frames for the life safety limit state using the DDBD method, although sidesway collapse check is also possible. Such amplification factor modifies the secant stiffness and strength of the design linear ESDOF system. The stability coefficient is estimated from an equation that is a function of the number of storeys and the column to beam stiffness ratios, which was defined from linear regression of the results of non-linear analyses of 8- to 15-storey frame structures. The seismic demands employed in such analyses were three sets of five synthetic spectrum-compatible records generated from the EC8 design spectra (CEN 2001); each set accounts for a different soil condition. The validation of their approach was carried out by comparison of the base shear amplification due to second order effects estimated with their approach and the shear amplification calculated using the EC8 criterion (CEN 2001) and a simplified equation proposed by Miranda and Akkar (2003) for SDOF systems. Hence, the criterion proposed in this article was validated at the ESDOF level only, as non-linear dynamic analysis of the multi-storey frames was not carried out. It should be noted that, as highlighted by MacRae (1994) and Pettinga and Priestley (2007), there is a conceptual problem regarding the consideration of P-Delta effects via the substitute structure as this artifice is based on the assumption that the equivalent system is self-centred, i.e., the response is reversible, assumption that is inconsistent with the behaviour of structures with severe P-Delta effects in which ratcheting of response occurs. Furthermore, P-Delta effects appear to be considered only at the ESDOF level without taking into account its influence in the distribution of storey design forces. Besides these conceptual problems, these proposals have been validated with a relatively limited size of synthetical or semi- synthetical records.
Mostrar más

105 Lee mas

Simplified modelling of bridge abutments-soil interaction under seismic effects

Simplified modelling of bridge abutments-soil interaction under seismic effects

ABSTRACT: A simplified model is proposed to show the importance that the dynamic soil-abutment interaction can have in the global behavior of bridges submitted to seismic loading.. The [r]

6 Lee mas

Fully probabilistic seismic risk assessment considering local site effects for the portfolio of buildings in Medellin, Colombia

Fully probabilistic seismic risk assessment considering local site effects for the portfolio of buildings in Medellin, Colombia

The exposure portfolio is a building by building resolution level database where every element is individually identified and characterized with the relevant parameters in terms of building class, number of stories and age in order to assign an adequate and representative vulnerability function. Building’s use and replacement values are required too in order to obtain the risk results in terms of sectors and monetary units respectively. For the defini- tion of those parameters, official indexes and statistics are employed. (Alcaldía de Medellín 2010). The information was complemented in some zones using aerial images. Several build- ing classes were identified in order to define a set of vulnerability functions that relate the intensity (spectral acceleration) with the expected loss (relative to the exposed value) in each element.
Mostrar más

25 Lee mas

Seismic behaviour of cable-stayed bridges : design, analysis and seismic devices

Seismic behaviour of cable-stayed bridges : design, analysis and seismic devices

Appendices B and C contain detailed information about the models, which have been extracted from the main body of the thesis to improve its legibility. Valuable details about the parametrization of the studied models are moved to appendix B, along with the dimensions of a large number of constructed cable-stayed bridges which have been used to establish the proportions of all the considered structures; sections of the towers (gures B.3 to B.7), deck, foundations and cable-stays, in- cluding the span arrangement in elevation and tower geometry. In this chapter, the most outstanding aspects of the parameterized models collected in appendix B are highlighted, whereas the support conditions are also discussed here. On the other hand, appendix C includes a detailed presentation of nonlinear material constitutive models, besides the results of specic studies about several modelling factors, like the appropriate nite element length in the towers taking into account the localiza- tion phenomenon. Furthermore, the comparison between experimental results on reinforced concrete cantilever beams and the numerical simulation with proposed nite element models is presented in appendix C, validating their use in nonlinear analysis.
Mostrar más

144 Lee mas

Response of reinforced concrete shear wall buildings during the 2010, Chile earthquake

Response of reinforced concrete shear wall buildings during the 2010, Chile earthquake

Figure 3-13 shows a wall of shell elements connected to the force-based fiber element used [21]. Both elements have the same section, but the fiber element incorporates several nonlinear behaviors for each type of fiber. The cyclic stress-strain relationship of concrete is based on the Kent and Park model [34], while the relationship for steel includes the monotonic curve as a bound of the cyclic behavior, the Bauschinger effect, and the bar buckling introduced through a softening region with a reduced stiffness when reloading from this zone. The softening slope gets steeper as the spacing of transverse reinforcement increases [21] (Figure 3-13(d)). All the fibers are regularized taking the length associated with each integration point, as explained elsewhere [21], where a detailed description of constitutive models can be found. The effect of tension strain prior to buckling, although experimentally observed and studied elsewhere [41], is not taken into account in the present study, since for this particular building, with walls subjected to high axial loads, the analyses show that maximum tension strains prior to failure are mainly in the elastic region of the steel curve, i.e. < 0.002.
Mostrar más

151 Lee mas

Comparación del comportamiento sismo resistente en puentes viga simple de acero con uso de aisladores de base con y sin núcleo de plomo

Comparación del comportamiento sismo resistente en puentes viga simple de acero con uso de aisladores de base con y sin núcleo de plomo

Abstract Abstract In the following document, a series of stages and procedures are going to be developed to analyze and compare the current and possible behavior of bridges to the effect of seismic ex[.]

135 Lee mas

Active patterns for self-optimization . Schemes for the design of intelligent mechatronic systems

Active patterns for self-optimization . Schemes for the design of intelligent mechatronic systems

The aim is to carry out self-optimization on the basis of mathematical models, e. g. using a realistic physical model of the controlled system supplemented by excitation and evaluation models. Frequently, it will not be practicable to use models for reasons of cost, so model-based self-optimization is combined with what is called “behavior-based self-optimization” which acts quasi-nondeterministic. This means that changes occurring during operation are sensed and analyzed, and then, depending on the results of this analysis, either another appropriate mathematical optimization model is loaded, or, if the limitations of available models are exceeded, the system reverts to using past experience in the form of learned structures or
Mostrar más

10 Lee mas

Inelastic torsional seismic response of nominally symmetric reinforced concrete frame structures: shaking table tests

Inelastic torsional seismic response of nominally symmetric reinforced concrete frame structures: shaking table tests

For low levels of seismic hazard, for which the structure is designed to perform basically in the elastic range (with minor damage), accidental eccentricity increases the lateral displ[r]

9 Lee mas

Modeling, analysis and seismic design of structures using energy dissipators SLB

Modeling, analysis and seismic design of structures using energy dissipators SLB

The SLB building corresponds to a precast building, regular in plan and elevation, for residential use located in an area of high seismicity in Peru. The proposed architectural project concerns infrastructure of five levels with a total height of 15.5m, as shown in figures 20 (a) and 20 (b). It has 4 apartments per level and rooftop. The objective is to design a safe, economical, functional and innovative structure in accordance with seismic standards, in addition to promoting the use of precast materials in favour of the industrialization of construction in the region [6]. The base structural proposal consists in a model equipped with devices of seismic protection, type Shear Link Bozzo (SLB). The resistant system is defined by square columns of 40cmx40cm, beams of 35cmx70m (of lengths greater than7 meters), precast unidirectional pre-slabs of 35cm and uncoupled concrete walls of 12cm. (Fig 20b).
Mostrar más

10 Lee mas

Show all 10000 documents...