Seismic analysis of Santa Maria del Mar church in Barcelona

Santa Maria del Mar és una joia arquitectònica construïda en només 50 anys en un estil gòtic pur i sobri. Acabada a finals del segle XIV, l’edifici inclou innovacions estructurals molt interessants compartides només, entre totes les construccions gòtiques, amb les catedrals de Barcelona i Mallorca. Aquest edifici es caracteritza per tenir 3 naus i no tenir creuer, creant un espai interior molt ampli gràcies a uns pilars molt esvelts i unes voltes amb grans llums.En aquest treball s’ha dut a terme una anàlisi estructural més acurada, aprofitant noves dades més precises sobre la morfologia de l’estructura. S’ha utilitzat un model de dany de tracció – compressió per a realitzar una Anàlisi per Elements Finits en la crugia tipus de l’edifici. Basat en la teoria del dany, té en compte el comportament diferenciat de l’obra de fàbrica a tracció i compressió

RC structures cyclic behavior simulation with a model integrating plasticity, damage, and bond-slip

The behavior of reinforced concrete structures under severe demands, as strong ground motions, is highly complex; this is mainly due to the complexity of concrete behavior and to the strong interaction between concrete and steel, with several coupled failure modes. On the other hand, given the increasing awareness and concern on the worldwide seismic risk, new developments have arisen in earthquake engineering; nonetheless, some developments are mainly based on simple analytical tools that are widely used, given their moderate computational cost. This research aims to provide a solid basis for validation and calibration of such developments by using computationally efficient continuum mechanics-based tools. Within this context, this paper presents a model for 3D simulation of cyclic behavior of RC structures. The model integrates a bond-slip model developed by one of the authors and the damage variable evolution methodology for concrete damage plastic model developed by some authors. In the integrated model, a new technique is derived for efficient 3D analysis of bond-slip of 2 or more crossing reinforcing bars in beam-column joints, slabs, footings, pile caps, and other similar members. The analysis is performed by implementing the bond-slip model in a user element subroutine of Abaqus and the damage variable evolution methodology in the original concrete damage plastic model in the package. Two laboratory experiments consisting of a column and a frame subjected to cyclic displacements up to failure are simulated with the proposed formulation

RC structures cyclic behavior simulation with a model integrating plasticity, damage, and bond-slip

Copyright © 2017 John Wiley & Sons, Ltd. The behavior of reinforced concrete structures under severe demands, as strong ground motions, is highly complex; this is mainly due to the complexity of concrete behavior and to the strong interaction between concrete and steel, with several coupled failure modes. On the other hand, given the increasing awareness and concern on the worldwide seismic risk, new developments have arisen in earthquake engineering; nonetheless, some developments are mainly based on simple analytical tools that are widely used, given their moderate computational cost. This research aims to provide a solid basis for validation and calibration of such developments by using computationally efficient continuum mechanics-based tools. Within this context, this paper presents a model for 3D simulation of cyclic behavior of RC structures. The model integrates a bond-slip model developed by one of the authors and the damage variable evolution methodology for concrete damage plastic model developed by some authors. In the integrated model, a new technique is derived for efficient 3D analysis of bond-slip of 2 or more crossing reinforcing bars in beam-column joints, slabs, footings, pile caps, and other similar members. The analysis is performed by implementing the bond-slip model in a user element subroutine of Abaqus and the damage variable evolution methodology in the original concrete damage plastic model in the package. Two laboratory experiments consisting of a column and a frame subjected to cyclic displacements up to failure are simulated with the proposed formulation.Postprint (author's final draft

Experimental study of concrete slab–base interaction for a seamless bridge–CRCP system

This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/JBENF2.BEENG-6076.Conventional bridge systems make use of expansion joints to accommodate movements caused primarily by thermal changes. These joints may accelerate the deterioration of bridge elements and often require significant maintenance costs. Originally proposed in Australia, the seamless bridge concept eliminates the need for expansion joints between bridge decks and roadway pavements. Past applications of seamless bridges have utilized a continuously reinforced concrete pavement (CRCP) in which a transition zone is employed between the bridge deck and the CRCP to accommodate the longitudinal expansion and contraction of the bridge and pavement. A critical aspect of the system response is the longitudinal load transfer mechanism in the transition zone, which is governed by the restraint at the concrete pavement–base interface. This paper presents an experimental investigation of the concrete slab–base interaction through unit-cell direct shear tests and cyclic full-scale push-off tests. The load (shear) versus displacement behavior at the interface was evaluated for different interface materials (geotextiles, polyethylene sheets, and felt paper). Test results indicated double-sided textured linear low-density polyethylene sheets and felt paper, which presented coefficients of friction of around 0.4 and 0.7, respectively, were the most promising interface materials to be considered for the transition zone.Peer ReviewedPostprint (author's final draft

Probabilistic Evaluation of Post-Earthquake Functional Recovery of a Seismically Isolated RC Building

All earthquakes throughout history have taught us that damage to non-structural elements and content has serious repercussions on the direct economic cost of damage and functionality. In essential buildings such as hospitals, rapid functional recovery is essential to safeguard the lives of the occupants and the injured who arrive after the earthquake. This study presents the detailed evaluation of the functional recovery of a RC seismically isolated 8 story hospital building located in an area of high seismicity. The study is carried out using the probabilistic analytical framework F-Rec, which has been recently proposed in the literature for the evaluation of the functional recovery of buildings after an earthquake. This framework complements the FEMA P-58 performance evaluation methodology allowing a complete and detailed evaluation of post-earthquake functionality, duration of damage and the path of functional recovery, considering structural and non-structural elements and content. In this study, a non-linear model of the building is created in OpenSees and the seismic response is studied for three hazard scenarios, Service Level Earthquake (SLE), Design Based Earthquake (DBE) and Maximum Considered Earthquake (MCE). Based on the results of the non-linear analyses, the damage losses are calculated using the FEMA P-58 tool, while the building recovery process is evaluated using the F-Rec framework. The efficient functional recovery time and route are analyzed for each scenario. The results show that the F-Rec framework is a viable tool for the evaluation of the post-earthquake functionality of isolated hospital buildings, but that there is a need to develop specific fragility and recovery curves for medical equipment.Peer ReviewedPostprint (published version

Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes

This paper summarises current research findings related to the behaviour and simulation of a relatively new type of structural component: recycled aggregate concrete-filled steel tube columns (RACFST). The first part of the paper presents a review of the latest experimental campaigns on RACFST columns subjected to a variety of loading conditions. For each of loading condition, highlight observations about the behaviour of RACFST columns are presented. The second part of the paper provides a summary of numerical modelling approaches developed for simulating the structural behaviour of RACFST columns. Special attention is paid to the selection and calibration of material models for recycled aggregate concrete. Finally, directions for future investigations in this area are outlined and discussed. The review will benefit researchers and professionals seeking to gain an indepth understanding of the behaviour of RACFST columns, and fills a gap in existing literature regarding a number of practical issues related to the numerical modelling of these components

3D strut-and-tie modeling for design of drilled shaft footings

Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration at the Center for Transportation Research of The University of Texas at Austin.A comprehensive study was conducted to characterize the structural response and develop design guidelines for drilled shaft footings. The study included large-scale testing and numerical analyses of footing specimens subjected to various loading conditions. A database of 35 drilled shaft footings constructed in Texas by TxDOT was established and analyzed for designing test specimens. A total of 19 large-scale specimens were designed and tested to study various design parameters and loading scenarios including vertical compression and uniaxial bending. A series of numerical analyses employing experimentally-verified models were also performed to account for the effect of additional design parameters that could not be covered in the experimental program. Based on the data and insights obtained from the experimental and numerical studies, 3D strut-and-tie modeling guidelines for drilled shaft footings are proposed by refining current provisions for 2D strut-and-tie models in AASHTO LRFD (2020). The new guidelines include the definition of the 3D nodal geometry at bearing faces, refinements for strength modification factors, critical section definitions for development of horizontal and vertical ties, and recommendations for bottom mat reinforcement configuration. Project findings have indicated that the proposed recommendations improve the accuracy of the ultimate strength predictions for a database including drilled shaft footing tests from the literature and the current study, without generating unconservative or overly conservative predictions. This represents an improvement of the accuracy achieved using the recommendations of TxDOT Project 5-5253-01. Lastly, a design example of a drilled shaft footing subjected to various loading scenarios is provided.Preprin

Development of Bridge Column Longitudinal Reinforcement in Oversized Pile Shafts

Publisher Copyright: © 2016 American Society of Civil Engineers.This paper presents an experimental investigation to determine the embedment length required for longitudinal reinforcement in a bridge column extending into an oversized pile shaft, and the amount of transverse reinforcement required for the pile shaft to prevent premature bar anchorage failure due to concrete splitting induced by bar slip. Four full-scale column-oversized pile assemblies were tested under quasi-static cyclic lateral loading. The test specimens had different embedment lengths for the column reinforcement, different amounts of transverse reinforcement in the piles, different sizes of longitudinal bars, ranging from No. 8 to No. 18 (25 to 57 mm) bars, and different column-to-pile diameter ratios. All column-pile assemblies behaved in a ductile manner with plastic deformation occurring near the base of the columns despite some cone-shaped fractures and tensile splitting cracks occurring in the top portion of the piles. The test results show that the embedment length for the column reinforcement can be significantly reduced as compared to that required in current design specifications. The study also shows that an engineered steel casing designed according to a formula proposed here can effectively confine the pile shaft and significantly reduce splitting cracks.Peer reviewe

Evaluation of Seamless Bridges

0-7011The research study included experimental testing and numerical modeling to obtain and develop much needed experimental data and analytical tools to study the performance of seamless systems, identify design issues, and propose design guidelines for the U.S. practice

Numerical modeling of the tension stiffening in reinforced concrete members via discontinuum models

[prova tipográfica]This study presents a numerical investigation on the fracture mechanism of tension stiffening phenomenon in reinforced concrete members. A novel approach using the discrete element method (DEM) is proposed, where three-dimensional randomly generated distinct polyhedral blocks are used, representing concrete and one-dimensional truss elements are utilized, representing steel reinforcements. Thus, an explicit representation of reinforced concrete members is achieved, and the mechanical behavior of the system is solved by integrating the equations of motion for each block using the central difference algorithm. The inter-block interactions are taken into consideration at each contact point with springs and cohesive frictional elements. Once the applied modeling strategy is validated, based on previously published experimental findings, a sensitivity analysis is performed for bond stiffness, cohesion strength, and the number of truss elements. Hence, valuable inferences are made regarding discontinuum analysis of reinforced concrete members, including concrete-steel interaction and their macro behavior. The results demonstrate that the proposed phenomenological modeling strategy successfully captures the concrete-steel interaction and provides an accurate estimation of the macro behavior