Suchergebnisse

Unreinforced masonry (URM) buildings are susceptible to extraordinary actions such as earthquakes compared to steel or reinforced concrete buildings. Various methods have been developed for the computational analysis of URM buildings in the last few decades. The equivalent frame method (EFM) is one of the numerical modeling approaches widely used for the nonlinear analyses of URM buildings. Different macroelements in the context of the EFM have been proposed. However, there is still a need for an efficient modeling approach in the computational effort that can predict the real behavior of URM structural components with sufficient agreement and available in opensource structural analyses software packages. For this purpose, a new macro-element based on the multiple vertical line element method (MVLEM) element has been developed in this study. The MVLEM is available in the OpenSees software platform comprising vertical uniaxial macro-fibers and a shear spring as an efficient macroelement for nonlinear analysis of flexure-dominated reinforced concrete walls. The novel macroelement, double modified MVLEM (DM-MVELM) element has been proposed consisting of two modified MVLEM elements tied with a nonlinear shear spring at the middle with a trilinear backbone behavior. DM-MVLEM can capture the axial-flexural interaction with lower computational effort than finite element models and fiber beam-column elements. The DM-MVLEM has been validated against the test results at the structural components level and a full-scale perforated URM wall. Unified method (UM) and composite spring method (CSM) are two existing EFMs that are presented in this study. A study is performed by comparing the seismic behavior of the perforated URM walls modeled using the UM, CSM, and DM-MVLEM modeling strategies. Results show that the DM-MVLEM can predict the damage patterns, and nonlinear behavior of spandrels can be simulated that was usually modeled with linear behavior in EFMs. ; This work is a part of the HYPERION project. HYPERION has received funding from the European Union's Framework Programme for Research and Innovation (Horizon 2020) under grant agreement No 821054. ; publishedVersion

Vibration-based finite element model (FEM) updating of cultural heritage assets is gaining so much attraction these days since destructive tests are usually not allowed to be performed. In this study, a framework for developing three-dimensional (3D) FEMs is proposed using 3D laser scanners and applied on Slottsfjell tower, a stone masonry tower in Tønsberg, Norway. Operational modal analysis (OMA) was done based on the ambient vibration testing (AVT) data to define the frequency values and corresponding mode shapes of the tower. Mechanical properties of the tønsbergite stone were utilized to derive the base values of the material properties of the homogenized masonry for performing sensitivity analysis and FEM updating. To investigate the effect of the soil-structure interaction (SSI) on the FEM updating results, three FEMs are developed. The fixed-base model is the FEM without considering the SSI effects, and two other FEMs are developed using the substructure and direct methods for simulating the SSI effects. Sensitivity analysis was performed to investigate the effective parameters on the dynamic characteristics of the models. FEM updating was conducted on the three FEMs, and results are compared to each other to show the role of the SSI on the FEM updating results. The resonance effect can cause damages to buildings located even in low seismicity zones. For this aim, the risk of resonance effect has been evaluated for the tower. Finally, linear dynamic analysis was performed on the three calibrated models, and the results were compared to each other. ; This work is a part of the HYPERION project. HYPERION has received funding from the European Union's Framework Programme for Research and Innovation (Horizon 2020) under Grant agreement no. 821054. ; publishedVersion

Cities in the developing world are facing outstanding economic and human losses caused by natural hazards such as earthquakes, and the amount of losses is affected by the quality of preventive measures and emergency management. For this reason, seismic vulnerability assessment is considered a crucial part of a strategy for seismic risk mitigation and for improving the resiliency of cities. Due to the high number of building archetypes for the seismic vulnerability assessment at a large scale, fast, simplified methods have been proposed that can facilitate the assessment procedure with low computational effort. Simplified methods can be categorized into three groups: analytical, empirical, and hybrid methods. In this study, simplified analytical methods for the seismic vulnerability assessment of unreinforced masonry (URM) buildings were reviewed, starting with their classification into three main groups: collapse mechanism-based, capacity spectrum-based, and fully displacement-based methods. Finally, attention was given to the corresponding software packages that were developed to facilitate the assessment procedure. ; This work is a part of the HYPERION project. HYPERION has received funding from the European Union's Framework Programme for Research and Innovation (Horizon 2020) under grant agreement No 821054. The contents of this publication are the sole responsibility of Oslo Metropolitan University (Work Package 5, Task 2) and do not necessarily reflect the opinion of the European Union. ; publishedVersion

The conservation of heritage structures is pivotal not only due to their cultural or historical importance for nations, but also for understanding their construction techniques as a lesson that can be applied to contemporary structures. Timber is considered to be the oldest organic construction material and is more vulnerable to environmental threats than nonorganic materials such as masonry bricks. In order to assess the structural vulnerability of heritage timber structures subjected to different types of risk, knowledge about their structural systems and configurations, the nature and properties of the materials, and the behavior of the structure when subjected to different risks, is essential for analysts. In order to facilitate the procedure, different assessment methods have been divided into the categories in situ and ex situ, which are applicable for vulnerability assessments at the element and full-scale level of a case study. An existing methodology for structural vulnerability assessments and conservation of heritage timber buildings is reviewed and a new methodology is proposed ; This work is a part of the HYPERION project. HYPERION has received funding from the European Union's Framework Program for Research and Innovation (Horizon 2020) under grant agreement no. 821054. ; publishedVersion

Recent studies highlight the potential impact of earthquakes on cultural heritage sites and monuments, which in turn yield significant adverse impacts on economies, politics, and societies. Several aspects such as building materials, structural responses, and restoration strategies must be considered in the conservation of heritage structures. Timber is an old organic construction material. Most of the historic timber structures were not designed to withstand seismic forces; therefore, the seismic vulnerability assessment of heritage timber structures in areas with high seismic hazard is essential for their conservation. For this purpose, different strategies for the numerical modeling of heritage timber buildings have been developed and validated against tests results. After performing seismic analysis using detailed analytical methods and predicting the susceptible structural components, strengthening techniques should be utilized to mitigate the risk level. To this aim, various methods using wooden components, composite material, steel components, SMA etc., have been utilized and tested and are reviewed in this study. There are still some gaps, such as full-scale numerical modeling of strengthened buildings and investigating the soil–structure interaction effects on the seismic behavior of buildings that should be investigated. ; This work is a part of the HYPERION project. HYPERION has received funding from the European Union's Framework Programme for Research and Innovation (Horizon 2020) under grant agreement No 821054. ; publishedVersion