Structural Masonry Walls Research Articles

Seismic Vulnerability Assessment of Multistory Timber Braced Frame Traditional Masonry Structures

Research carried out on the seismic investigation of timber braced frame (TBF) masonry structures of traditional construction practice is presented, essential for seismic performance evaluation of such construction type using engineering approaches. An innovative simplified equivalent frame method (EFM) based on macro modelling approach is presented for nonlinear dynamic seismic analysis of TBF masonry structures. The modelling include EFM idealization of wall using stiff elastic beam-column element assigned with moment-rotation (M-θ) nonlinear lumped plasticity hinges. Earlier, the approach i.e. the EFM idealization and M-θ constitutive law, is calibrated with the experimental results obtained through quasi-static cyclic test on full scale walls. The technique is further extended herein for seismic dynamic analysis of multistory structures. Generalization of the technique for modelling walls of various geometry and loading is performed. It included nonlinear static pushover analysis of various case study walls, by means of SAP2000 calibrated earlier with experimental results, for the derivation of lateral force-deformability behavior towards the development of generalized M-θ constitutive law for TBF masonry walls. Three representative structures, from one to three storeys, are analyzed using a suite of ten natural accelerograms and incremental dynamic analysis technique. Structure fragility and resilience functions are derived using a fully probabilistic and dynamic approach. The structures analyzed in the present study represent TBF masonry wall structures, called as Dhajji-Dewari structures, common in Northern areas of Pakistan.

Analysis of Failure Mode of Masonry Wall under Vertical Compressive Stress

The application of ABAQUS finite element software non-linear finite element analysis of brick masonry walls with structural column. Build three brick masonry wall models, and analysis of the damage form of the wall under different vertical compressive stress and horizontal force. Thus the analysis result compared with the calculation result of the relevant specification formula, in order to get validate compression influence of masonry aseismic walls. It turned out that different vertical compressive stress effect the shear capacity, and failure mode of brick masonry wall structure with a structural column.

Simplified engineering tools for seismic analysis and design of traditional Dhajji-Dewari structures

This paper presents simplified engineering tools for seismic analysis of traditional Dhajji-Dewari structures, a concentrically braced timber frame with masonry infill, within the context of vulnerability assessment of existing stock, strengthening and restoration of historical heritage and feasibility analysis of future construction projects. Similar like structures can be found in various parts of America, Asia, Europe and the Middle-East. The study included tools for the evaluation of lateral force-deformability characteristics of Dhajji walls using non-linear static pushover analysis, simplified models for nonlinear dynamic time history analysis of Dhajji wall structures subjected to ground shaking, and simplified models for seismic performance evaluation of Dhajji wall structures using hand calculations. Three full scale Dhajji walls tested quasi-static-cyclically, with additional 18 tension and bend tests on timber frame connections, at the Earthquake Engineering Center of Peshawar are analyzed to understand the damage mechanism and salient features of the system in resisting lateral load, retrieve lateral force-deformability behavior, hysteresis response and viscous damping (energy dissipation) of Dhajji walls in order to calibrate tools for nonlinear static and dynamic seismic analysis of Dhajji wall structures. Applications are shown on the seismic performance assessment of example structures and design of new construction schemes. The findings from the present research study can provide help on the seismic performance evaluation of similar like concentrically braced timber frame masonry wall structures.

Force- and Displacement-Based Seismic Performance Parameters for Reinforced Masonry Structural Walls with Boundary Elements

AbstractThere is a need to evaluate existing, and introduce new, masonry construction techniques within a performance-based seismic design context to advance their adoption in the next generation of seismic design codes in North America. In this regard, a reinforced masonry (RM) structural wall system that incorporates confining boundary elements in the plastic hinge region presently lacks specific design requirements in the Masonry Standards Joint Committee and Canadian Standards Association S304.1 design codes. In addition, RM structural wall systems are omitted completely from the plan to develop a new performance-based seismic design methodology laid out by FEMA 445. This paper presents experimental results of four specially detailed RM structural walls subjected to fully reversed cycles of displacement-controlled loading as tested by the authors. In addition, the resulting analysis also includes one wall from a previous study for comparison purposes. All walls were detailed with lateral reinforcing t...

EVALUATION OF HORIZONTAL MOVEMENTS OF MASONRY WALL,“TSUKIISHIBU”,UNDER DYNAMIC HORIZONTAL LOAD

Vibration tests were performed in order to quantify horizontal movements of TSUKIISHIBU section in masonry wall subjected to dynamic horizontal load; the TSUKIISHIBU section represents the whole part of the masonry wall structure excluding corner part. A wall model was constructed by rectangular prism shaped masonry stones with kinds of slope on dry sand backfill and sinusoidal motion was applied on shaking table. The horizontal movements of masonry walls concerning such variables as slope angles, internal friction angles of stone blocks and back fill soil and input acceleration were calculated. As horizontal movements of masonry wall models show good agreement with calculated horizontal movements of the wall, validity of the theory for predicting horizontal movements of the wall is clarified.

Nonlinear response of masonry wall structures subjected to cyclic and dynamic loading

The assessment of the dynamic or seismic performance of complex structures often requires the integration in the time domain of the structural equation of motion in the frame of a nonlinear analysis. Although sophisticated methods have been developed for the nonlinear analysis of masonry wall structures, including the macro- and micro-modeling approaches, these require large computational effort still limiting the extent and complexity of the structures analyzed. This paper presents an alternative method based on the Generalized Matrix Formulation for masonry skeletal structures and load bearing wall systems, which has been proved as an efficient formulation for the analysis of the strength capacity of these kinds of structures (Roca et al. (2005) [17]). The basic formulation has been complemented with a uniaxial cyclic constitutive model for masonry and a time integration scheme. The ability of the resulting approach to predict the nonlinear dynamic response of masonry structures is shown through its application to the time domain analysis of an experimental scale masonry building with available experimental results on its dynamic response.

Non Linear Response of Masonry Wall Structures Subjected to Cyclic and Dynamic Loading

A method for non-linear dynamic analysis of wall masonry structures is presented. The method takes advantage of a Generalized Matrix Formulation (GMF) for the serviceability and ultimate analysis of structures composed of arches and/or masonry walls, in which open and solid walls are described as equivalent frame systems. This formulation has been complemented with a cyclic constitutive model and an algorithm for the integration of the equation of motion, resulting in a numerically efficient method for non-linear analysis in time domain of complex masonry systems.

Vertically perforated clay brick masonry for loadbearing and non-loadbearing masonry walls

The work presented in this paper deals with the development of a solution for structural masonry walls to be used in zones with different seismic hazard and also a solution for enclosure walls for replacement of traditional cavity walls. A key concern on modern construction is sustainability, particularly with respect to energy efficient buildings, as energy consumption of buildings represents a significant share of the total consumption of energy. The novel clay masonry unit proposed here ensures an appropriate thermal and mechanical performance. Besides the description of the optimization process to obtain a proper thermal performance, the paper addresses mechanical validation based on a set of experimental tests carried out on units and masonry walls under uniaxial compressive loading. Additionally, a set of in-plane cyclic tests were carried out on masonry walls in order to assess the performance of the system under seismic loading. The results indicate that the proposed masonry unit leads to adequate thermal and mechanical behavior.

Seismic Response Modification Factors for Reinforced Masonry Structural Walls

The current North American design standards provide seismic force modification factors for the rectangular masonry structural walls category only; no similar provisions for flanged and end-confined masonry structural walls exist. This study demonstrates that seismic force reduction factor (R) values calculated for rectangular walls was close to 5.0, which is consistent with the value stipulated by the ASCE 7, and was 36 and 90% higher for the corresponding flanged and end-confined walls. The deflection amplification factor (Cd) values calculated for rectangular walls were higher than specified in the ASCE 7 for the special reinforced masonry wall category. Values of the ductility-related force modification factor (Rd) for flanged and end-confined walls were, respectively, at least 30 and 100% higher than those of rectangular walls specified in the National Building Code of Canada (NBCC). Quantification of the seismic response parameters within this study is expected to facilitate adoption of the flanged a...

An integrated diagnostic approach for the assessment of historic masonry structures

Abstract Knowledge of the structural behaviour of existing masonry requires a multi-level approach, with the proper application of diagnostic and assessment methodologies. The structural performance of masonry wall structures can be understood provided that the history of their construction, their geometry, the characteristics of their masonry texture, and the characteristics of the masonry as a composite material are known. In order to obtain all these data, an effective on-site testing program, which can involve the application of different test methodologies as a combination of destructive tests (DT), minor destructive tests (MDT) and non-destructive tests (NDT), needs to be performed. Furthermore, the effectiveness of applied methodologies for the assessment of historical masonry structures strongly depends on the type of investigated structure, as well as on the appropriate numerical model for the analysis. However, the unclear aspects of any testing programme remain the same – how efficient is a particular testing technique, and how can it be assessed? Following the results of recently carried out EU and national research projects, a comprehensive set of data regarding the effectiveness of different testing methods, depending on the type of problem, have been collected and analyzed. Within this framework, several masonry heritage structures from Slovenia, which differ both from the historical and structural point of view (Pisece Castle, the Carthusian Monastery at Žice, and a typical stone-masonry house from the Soca Valley region), have been investigated by means of different techniques, and numerically analyzed. For this purpose, two different models were used: a push-over model based, on the structural element method, and FEM analysis. It was concluded that the effectiveness of any particular diagnostic technique for the investigation of masonry structures, and for the planning of their restoration, depends on numerous factors. An attempt to determine which of the techniques could be appropriate, depending on the problem, was made. No single test is self-sufficient for the solving of a particular problem, so a combination of different NDT, MDT and DT should be performed. Summarizing all the results, it can be said that, in the process of assessing the state of a structure, even a simple investigation technique is better than none. The effort will always be repaid - if not already in the planning stage of the restoration and retrofitting actions, then certainly in the execution stage of the revitalization works, on site.

Assessment of Structure Through Non-Destructive Tests (NDT) and Minor Destructive Tests (MDT) Investigation: Case Study of The Church at Carthusian Monastery at Žiče (SLOVENIA)

Increasing the knowledge of the structural behavior of existing masonry requires a multi-level approach, with proper application of diagnosis and assessment methodologies. The structural performance of a masonry wall structure can be understood provided that its geometry, the characteristics of its masonry texture and the general characteristics of masonry as a composite material are known. For the compilation of all required data, an effective on-site testing campaign is needed, including the application of different test methods by means of combination of minor destructive tests (MDT) and non-destructive tests (NDT). The case study presented herein, encompasses experimental work carried out at the Church of St. John the Baptist at the Carthusian monastery at Žiče, Slovenia. Within this project, on-site investigation was carried out in order to characterize wall cross-sections, to identify different types of masonry, and to collect the samples of mortars and stone particles for further laboratory tests. Methods that were applied for this case study were: crack pattern investigation, radar investigation of masonry walls and internal structure of the ground in the Church, thermography, coring, and boroscopy, as well as laboratory tests on cored samples.

石垣築石部の長期荷重時崩壊挙動に関する模型実験

Model tests were performed in order to obtain collapse behavior of TSUKIISHIBU section in masonry walls under long-term load; the TSUKIISHIBU section represents the whole part of the masonry wall structure excluding corner. A wall model was constructed by rectangular prism shaped masonry stones placed one on another with initial angle of slope on dry sand backfill, and the angle of slope was increased quasi-statically until the model collapses. It is observed that when the initial angle of slope is steep the model collapses with overturning mode of the wall and when the initial angle of slope is relatively mild the model collapses as if the wall was bending at the middle height. As wall heights that the model collapse show good agreement with critical slope curves those are theoretically obtained, validity of the theory for predicting critical height of the wall is clarified.

Strength Capacity of Masonry Wall Structures by the Equivalent Frame Method

The structural assessment of large traditional and historical masonry buildings poses significant challenges due to the need for modeling complex geometries and nonlinear material behavior. Although sophisticated methods have been developed for the nonlinear analysis of such structural systems—mostly based on two- or three-dimensional finite element modeling—they can hardly be used for practical purposes due to very large computational requirements. This paper presents an alternate method, specifically developed for efficiently simulating the service and ultimate responses of structural systems composed of masonry load-bearing walls. Its efficiency stems from the technique adopted to model the wall panels, based on treating them as equivalent frame systems composed of one-dimensional elements. In addition, biaxial constitutive equations are included to account for the relevant aspects of the nonlinear response of the material. In spite of the numerical efficiency of the method, it is able to obtain accura...

Shearing Capacity of Masonry Structural Walls Strengthened by CFRP Plates

Shearing Capacity of Masonry Structural Walls Strengthened by CFRP Plates

Reversed In-Plane Cyclic Behavior of Posttensioned Clay Brick Masonry Walls

A series of five large scale clay brick masonry structural walls are subjected to in-plane simulated seismic forces. The walls utilize posttensioning steel to provide flexural strength. The primary objective of the research is to investigate five basic configurations of posttensioning to determine which has the most desirable characteristics for seismic performance. In the study, the variables of interest were ! 1 bonded versus unbonded posttensioning steel, ! 2 confined versus unconfined masonry, ! 3 grouted versus ungrouted masonry, and ! 4 application of supplemental mild steel for energy dissipation. Following the results of the tests, it was shown that the best performing configuration utilized unbonded posttensioning and confinement. By utilizing unbonded posttensioning, walls have little residual deformation after loading, thus yielding structures that would require very little repair, even after large seismic events. Such behavior comes with the price of reduced energy dissipation, however. Presented in the paper are the results of the tests as well as results of a simple analysis method for prediction of wall capacity.

城郭石垣構造の力学安定

Japanese Castle masonry walls constructed from the end of sixteen century to the middle of seventeen century hold a historical heritage in the construction culture and are famous worldwide for their uniqueness with mortar-less construction. Present investigations on these walls have shown bulging at various locations and the engineering evaluation on the wall stability needs to be urgently required. Based on this viewpoint, this paper presents the FEM analysis results on the stability and deformation behavior with parametric analyses on Osaka Castle masonry wall. It is found that the cobble plays a significant role in reducing the stresses of stone wall and that the masonry wall structure ratio adds stability by the arching effect action on the masonry wall.

MIXED INTEGER PROGRAMMING FOR THE OPTIMAL (LEAST COST) DESIGN OF ECCENTRICALLY LOADED MASONRY BEARING WALLS: PART I. LOW ECCENTRICITIES

A mixed integer approach for the least cost design of structural masonry walls with high eccentricities is developed. The integer variables in the approach are used to select the optimum values from a range of discrete block sizes, discrete grouting conditions, and discrete reinforcement levels. The structural constraints in the model are based upon the requirements of the Transformed Section type of analysis for masonry walls. The non-linear functions representing the relationships for determining the resisting capacities of the masonry element are approximated by linear functions which come very close in form and results to the original curves. Application of the model to an example problem demonstrates that in spite of the integer requirements, the approach is easily and efficiently solved using a standard software package.

MIXED INTEGER PROGRAMMING FOR THE OPTIMAL (LEAST COST) DESIGN OF ECCENTRICALLY LOADED MASONRY BEARING WALLS:Part II. High Eccentricities

A mixed integer approach for the least cost design of structural masonry walls with high eccentricities is developed. The integer variables in the approach are used to select the optimum values from a range of discrete block sizes, discrete grouting conditions, and discrete reinforcement levels. The structural constraints in the model are based upon the requirements of the Transformed Section type of analysis for masonry walls. The non-linear functions representing the relationships for determining the resisting capacities of the masonry element are approximated by linear functions which come very close in form and results to the original curves. Application of the model to an example problem demonstrates that in spite of the integer requirements, the approach is easily and efficiently solved using a standard software package.

A proposal for the compatibility of static and dynamic seismic base shear provisions of the National Building Code

A comparison is made, based on static and dynamic base shear calculations according to the National Building Code of Canada of 1980, for four types of simple structures, namely, uniform moment resisting frame structures, uniform ductile flexural wall structures, uniform reinforced concrete shear wall structures, and unreinforced masonry wall structures. It is shown that a significant discrepancy exists between the static and dynamic base shear values, depending on the type and the fundamental period of the structure. The causes for the discrepancy and the necessity to make static and dynamic base shears compatible are discussed.