1 PhD Student, Centre for Infrastructure Performance and Reliability, The University of Newcastle, University Drive,
Callaghan, NSW, Australia, lewis.gooch@uon.edu.au
2 Professor, Centre for Infrastructure Performance and Reliability, The University of Newcastle, University Drive,
Callaghan, NSW, Australia, mark.masia@newcastle.edu.au
3 Professor and Director, Centre for Infrastructure Performance and Reliability, The University of Newcastle,
University Drive, Callaghan, NSW, Australia, mark.stewart@newcastle.edu.au

ABSTRACT
A detailed and accurate stochastic analysis of a structure allows for greater insight into the variability of potential failure mechanisms than simplified analytical or deterministic finite element models. Furthermore, this technique facilitates an estimation of the reliability of the type of structure under examination. In order to perform an accurate stochastic numerical analysis of unreinforced masonry walls, the finite element model must be calibrated via experimentally obtained material properties as well as a baseline structural response. This facilitates the greatest accuracy for the applied numerical simulations and allows for an estimation of the model error of future simulations not compared to an explicit experimental counterpart. Considering an existing, detailed experimental study, a modelling strategy for examining unreinforced masonry walls with spatially variable material properties was developed. These analyses were able to estimate the
mean load resistance of the examined walls with a greater accuracy than a deterministic model, as well as capturing the variability of shear capacity and the observed damage to the experimentally
tested walls. As the tested specimens failed almost exclusively in a rocking mode, a failure mechanism highly dependent upon the structures’ geometry, the variability of the peak strength
was minimal. However, the observed damage and presence of some local sliding and stepped cracking indicates that the proposed methodology is likely to capture more variable and unstable failure modes in shear walls with a smaller height-to-length ratio or those subject to greater precompressions.

KEYWORDS: arched brick wall, monte-carlo simulation, shear wall, spatial variability,stochastic finite element analysis, unreinforced masonry

118-Gooch.pdf

¹ Structural Engineer, Parsons Brinckerhoff Halsall Inc., Toronto, ON, M4P 1E4, Canada, email dlaird@halsall.com

ABSTRACT
CSA S304.1-04 “Design of masonry structures” uses an engineered design method (limit states design), but also permits the use of an empirical design method. The empirical approach is only allowed for unreinforced masonry and only if the building and its location are within specified limits for building height, seismic hazard index and hourly wind pressure. Many locations in Canada are ruled out by the seismic and wind limitations. Those locations remaining are mainly in parts of the Prairies and Ontario. When unreinforced masonry walls are designed for wind and seismic loading in accordance with the engineered design method, the walls are often significantly stronger than required by the empirical design method. Should this be allowed to continue or should the two design methods be reconciled? That is the dilemma. This paper discusses the two design methods and gives example calculations to compare the two. The relevant changes to the two design methods, the design loadings, and masonry construction over the past 50 years are discussed. Some relevant differences with the current American masonry code are also mentioned. Possible reasons are examined as to why the empirical design method has had such a successful history and why the empirical design method continues to be permitted. Some recommendations are included.

KEYWORDS: empirical design, limit states design, flexural tensile strength, wind load, seismic load, reliability analysis

471.pdf

¹ Professor, Department of Civil Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada, ngshrive@ucalgary.ca
² Coordinator, Canada Masonry Design Centre Calgary Office, 2725 12th St NE, Calgary, AB, T2E 7J2, Canada, guzman@canadamasonrycentre.com

ABSTRACT
Clauses for the design of masonry arches have been introduced into the Canadian masonry design standard (CSA S304) for the first time. In the engineered section the clauses are purposefully broad in concept as there are so many possibilities for arch shape, span and depth. Specifics, for example on how many spandrels should be placed in a road or railway bridge are avoided, as is lateral stability of the arch. The clauses therefore are aimed at the design of the arch itself, requiring design as a fixed arch if the abutments are fixed. The alternative is for the designer to allow for estimated relative movement of the abutments or design the arch as a two-pin arch. In the assessment of live-loading, stability is considered allowing a maximum of three hinge locations to be produced. These can be reinforced. For more information on arch analysis and design, the designer is referred to a document available from the Canada Masonry Design Centre. Tables have been developed for the empirical section of the code specifying minimum column widths for low-rise arches of different spans and depths supported on columns. The formulae and basis of the calculations are provided. This is to allow designers to use small span arches in veneers of either brick or block without having to do detailed calculations.

KEYWORDS: arch, design, analysis

609.pdf

I-XL Industries Ltd. Brick Group

INTRODUCTION
Brick is one of man’s oldest manufactured products. No doubt the caveman noticed that where fire sat on a clay base it turned mud into a hard material. From there it was a short step to shape that mud and develop pottery which has been one of archeologists’ principal dating methods. Pottery is remarkable for its durability. except when dropped on my tile kitchen floor.
The evolution from pottery to brick no doubt developed as need to have a durable building product in those areas that lacked readily available wood or stone. The advantages of a rectangular building product over a rough stone product are obvious. The laying of brick certainly would be easier than the laying of stone…

9518.pdf

¹ Portland Cement Association, 5420 Old Orchard Rd., Skokie, IL, 60077, USA
² National Concrete Masonry Association, 2302 Horse Pen Road, Herndon, VA, 20171, USA

ABSTRACT
This paper investigates the relationship between the flexural strength of concrete masonry walls and prisms constructed using masonry cement mortars. Results obtained in this study are compared to results from previous studies and conclusions are presented with respect to the potential flexural bond strength of concrete masonry constructed with masonry cement mortars.
The research included testing of concrete masonry specimens using Type S masonry cement mortars. Three different cement manufacturers supplied the masonry cements. Ten walls were constructed for each of the mortars using nominal 203x203x406-mm (8x8x 16-in.) hollow concrete masonry units. Flexural strengths of wall walls were determined in accordance with ASTM E 72. A uniform transverse load was applied over the face of the wall specimens by pressurizing an air bag sandwiched between the wall and a rigid test frame.
Three companion two-unit, stacked-bond prisms were fabricated during the construction of each wall and were tested in flexure using a bond wrench apparatus. In addition, the flexural bond strength of each mortar in combination with standard concrete testing brick was determined. Six prisms, each containing five mortar joints, were fabricated using controlled fabrication and curing.

6038.pdf

Canadian Masonry Contractors Association

2338.pdf

¹ Ph.D., P.Eng., Heritage Conservation Program. Public Works and Government Services Canada, Hull K1A 0M5
² Professor, Department of Civil and Environmental Engineering. Carleton University, Ottawa. Canada K1S 5B6

ABSTRACT
Traditionally, masonry design in Canada has been carried ollt using the Working Stress Design (WSD) method and utilizing procedures that were developed in part through theoretical and experimental studies and also through traditional practice and experience. More consistent levels of safety and economic efficiency can be achieved by incorporating the Limit States Design (LSD) approach in the design of masonry structures just as in the design of steel and concrete structures. The 1995 publication of CSA Standard S304. l-94, Masonry Design for Buildings (LSD), is providing designers with a LSD procedure for masonry design. Consequently, the LSD approach also had to be extended to cover the design of masonry connectors. The publication of the 1994 CSA Standard AJ 70, Connectors jor ,\lasomJ’. provides designers with LSD procedures for the design of connectors for masonry. This paper deals with the factored resistance of masonry connectors and the background behind selecting different values for the resistance reduction factor ¢.

0058.pdf

Department of Civil Engineering, University of New Brunswick Fredericton, NB, Canada, E3B 5A3

ABSTRACT
The effect of the wall aspect ratio, a = H / L, beam-to-column inertia ratio, fJ = h/ le, and the effect of openings on the In-plane stiffness of reinforced concrete infilled frames has been investigated. Tests were conducted on forty eight one­third scale models of RC frames from which the initial tangent stiffness, K;, the secant stiffness at first crack, Kc, and the secant stiffness at ultimate, Ku , were determined. Although the three parameters markedly affected the in-plane stiffness of infilled frames, the aspect ratio did not have a significant effect on K , A unit increase in aspect ratio resulted in fifty percent reduction of Kc. Although the effect of the beam-to-column inertia ratio on Kc and Ku depended on the opening coefficient, a unit increase lh fJ resulted in more than ten percent increase of the initial stiffness. Regression analyses were performed on test results and yielded empirical formulations which could be used in assessing the stiffness of RC frames infilled with masonry panels.

1098.pdf

Department of Civil & Environmental Engineering,
University of Bradford, Bradford, West Yorkshire, England. BD7 IDP.

ABSTRACT
A numerical method of estimating the strength of masonry arches is presented. The method is based on a mechanism analysis of the arch at collapse with the failure mode idealised as an assemblage of rigid blocks separated by zones of displacement discontinuity; the masonry is assumed to be rigid-perfectly plastic. The shape and position of the fracture lines and the displacement of the rigid blocks of masonry are the variables in the energy equation. Minimisation of the predicted collapse load produces the optimum shape and position of the fracture lines. Comparisons of the predicted collapse loads and crack patterns at failure show good agreement with the results obtained from model tests in the laboratory.

1138.pdf

Whitlock Dalrymple Poston & Associates, Inc.
Manassas, Virginia USA

ABSTRACT
Reinforced and non-reinforced masonry walls rely upon grout to provide axial, shear and bending load resistance. Grout must be well consolidated to sufficiently bond to horizontal and vertical reinforcing steel to transfer stresses between the grout and the reinforcement. If voids are present, adequate bond may not be provided. In addition to affecting structural integrity, missing grout and voids will allow water to collect around reinforcement leading to corrosion and, potentially, leakage to the interior. Unlike reinforced concrete which can be inspected after form removal, masonry voids go undetected because the masonry units remain in place concealing the grout and voids.
Destructive and non-destructive methods for determining the presence of voids, their locations and delineation of the size of voids in masonry walls are discussed. These methods include infrared thermography, impact-echo, impulse radar, test borings, human range audible soundings and random demolition. The non-destructive methods may be employed during construction for quality assurance or in the investigation of existing structures for rehabilitation.

1298.pdf