1. Associate Professor, College of Architecture, Georgia Institute of Technology, Atlanta, Georgia, USA, russell.gentry@coa.gatech.edu
2. Doctoral Candidate, College of Architecture, Georgia Institute of Technology, Atlanta, Georgia, USA, andres.cavieres@gatech.edu
3. Visiting Assistant Professor, College of Architecture, Georgia Institute of Technology, Atlanta, Georgia, USA, tristan.al-haddad@arch.gatech.edu

ABSTRACT

This paper, explores the extent to which concepts of parametric modeling can be applied to support the design process of load-bearing masonry buildings. The research uses the concepts of building information modeling and parametric representation to capture and execute relevant constructive knowledge for the design of doubly-curved masonry walls. Prototype software has been developed to translate this knowledge into a set of explicit parametric rules and geometric constraints which “bound” the curvatures of the masonry walls to those with admissible construction and structural solutions. Rules for calculation of vertical and horizontal reinforcement placement of rebar in grouted cells and bond beams have been developed to allow for preliminary design of doubly-curved walls. The software operates within a CAD environment and provides real-time feedback on wall configuration and reinforcement as the model is built. The paper reviews the rules necessary for block wall description, including door and window openings, and focuses on the calculations necessary for preliminary structural design of doubly-curved load-bearing masonry walls.

KEYWORDS: building information modeling, parametric modeling, concrete masonry units

C8-2

1. Engineer, OPUS Architects & Engineers, Minnetonka, MN 55343, USA, jennifer.popehn@opus-ae.com
2. Professor, Dept. of Civil Engineering, Univ. of Minnesota, Minneapolis, MN 55455, USA, schul088@umn.edu
3. Prof., Dept. of Civil & Architectural Engineering, Univ. of Wyoming, Laramie, WY 82071, USA tannerj@uwyo.edu

ABSTRACT

The buckling strength and deformation capacity of an unreinforced masonry wall (URM) can be significantly affected by both initial imperfections and axial load eccentricity. To account for this decrease in strength, the 2008 TMS-402 (i.e., United States (US) masonry design provisions) Strength Design chapter includes a new provision for including second order effects through a moment magnifier. However, this method of treatment has limitations: initial imperfections are essentially not considered when the eccentricity is larger than 10% of the wall thickness. Additionally, when designing using Allowable Stress Design (ASD), the second order bending effects arising from axial load are ignored. To determine the accuracy of the ASD and SD provisions, the calculated moment magnifiers were compared to experimental data from seven slender URM wall tests conducted at the University of Minnesota. In the experimental study, three of the walls were constructed of cored clay brick, while the remaining four were fabricated using hollow concrete block. The simply-supported masonry wall tests began with a pre-selected axial load which was applied to the walls in force control using two vertical load actuators and held constant throughout the tests. After the axial load was applied to the walls, lateral load was applied with a whiffletree system operated in displacement control. The lateral displacement was increased until all lateral load capacity had diminished.

KEYWORDS: slenderness, imperfection, second order, axial load eccentricity, unreinforced masonry, buckling strength

C8-1

1. Professor Emeritus, Centre for Effective Design of Structures, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, drysdale@mcmaster.ca
2. A.Sc. Candidate Department of Civil Engineering, McMaster University, wierzbj@mcmaster.ca
3. A.Sc. Candidate Department of Civil Engineering, McMaster University, hughekj@mcmaster.ca
4. A.Sc. Candidate Department of Civil Engineering, McMaster University, bantinbr@mcmaster.ca
5. Martini Mascarin and George Chair in Masonry Design, Centre for Effective Design of Structures, Department of Civil Engineering, McMaster University, eldak@mcmaster.ca

ABSTRACT

In modern house construction, the use of increased head room and the trend toward greater depths of backfill have led to reduced use of concrete block in basement construction. This paper provides conceptual information on use of 20 cm concrete block basement walls fitted with external surface mounted ties anchored into the top and bottom of the wall to create tied arch action. Test results verify that this structural system works well. It also provides a cost efficient alternative to existing basement wall construction systems with minimal changes to traditional construction techniques.

KEYWORDS: arching, backfill, basements, bending, concrete block, reinforcing, soil pressure, tied arch, ties.

C7-3

^1,2 University of Windsor, Windsor, ON, N9B 3P4, Canada

³ Canada Masonry Design Centre, Mississauga, ON, L5T 2N7, Canada

ABSTRACT

The current Canadian standard recommends strength reduction factors of 0.5 and 0.7 when compressive force is applied normal to the head face (parallel to the bed face). This strength reduction factor value is 0.7 if the grout is horizontally continuous (when there is no web interruption in the grout) and it is 0.5 if the grout is not horizontally continuous (when web interruption exists). It is argued that the reduction factors (0.5 and 0.7) suggested in the Canadian standard is highly conservative and is not based on any detailed study. Thus, a detailed research program based on experimental study on prism specimens with three levels of grout interruption was undertaken. The prism specimens were loaded in two different directions: (i) parallel to the bed face and (ii) perpendicular to the bed face. Varying degrees of web interruption were incorporated in the prism specimens to investigate the effects of various levels of web interruption on the compressive strength when loaded normal to the head face. This paper discusses the test specimens and test methods used and the results obtained from the study.

KEYWORDS: masonry prism specimens, loading parallel to bed face, grout interruption, strength reduction factor

B8-3

1. Associate Professor, School of Civil Engineering, Harbin Institute of Technology Harbin, Heilongjiang, 150090, China, xmzhai@hit.edu.cn
2. Senior lecturer, Centre for Infrastructure Performance and Reliability, School of Engineering, The University of Newcastle Newcastle, NSW, 2308, Australia, Yuri.Totoev@newcastle.edu.au
3. Professor, Centre for Infrastructure Performance and Reliability, School of Engineering, The University of Newcastle Newcastle, NSW, 2308, Australia, ,Mark.Stewart@newcastle.edu.au

ABSTRACT

A reinforced grouted concrete block wall/beam, composed of cast-in-place concrete beam and reinforced grouted block wall, is common in mixed retail/commercial and residential construction in China. Often the ground floor houses a shop and commercial storage and residential flats are built on the floors above. In such buildings the ground floor is built as a reinforced concrete (RC) frame with or without shear walls and the upper floors are built with walls of reinforced grouted concrete blocks. According to Chinese code, the RC beam depth to span ratio for wall/beam composition should be greater than or equal to 1/6 for seismic design. Compared to a RC beam with unreinforced masonry (URM) wall on top of it, the reinforced grouted concrete block wall/beam structure has greater stiffness. The higher stiffness can help reducing the cast-in-place RC beam depth to span ratio, and thus increase the height of the ground floor. In this paper, test results for six different wall/beam compositions are presented. The structural capacity, the load-deformation relationship, force-transferring path, and failure mode are examined. The experiments show that the reinforced block wall/beam acts like a deep beam. It was found that the RC beam depth to span ratio can be reduced from 1/6 to 1/10.5.

KEYWORDS: reinforced grouted concrete block, wall/beam, depth to span ratio

B8-1

1. Wembley Innovation Ltd, Atlas Road, Wembley, Middlesex, HA9 0JH, United Kingdom, hamish.corbett@wembleyinnovation.co.uk
2. CERAM, Queens Road, Penkhull, Stoke-on-Trent, Staffordshire, United Kingdom, geoff.edgell@ceram.com

ABSTRACT

In 2006 CERAM began an experimental programme to investigate the performance of large blockwork walls, reinforced at intervals up their height by bond beams[1]. The concept was developed by Wembley Innovation as a simple alternative to the use of wind posts. The performance of the walls was very encouraging and lateral loads in the region of 6kN/m² were satisfactorily resisted. Since the initial tests various configurations of the walls, for example wall height to length ratios have been varied, the introduction of windows and door openings have been investigated and the connections to the framing elements of the building have been refined. In order to introduce the system to the mainstream of structural engineering consultants in the UK and elsewhere CERAM produced a design procedure which has been developed in conjunction with consultants Jenkins and Potter and Buro Happold. The procedure essentially builds upon the approach in the UK for the design of walls containing prefabricated bed joint reinforcement and incorporated in BS 5628: Part 1. As current UK Codes of Practice[2] are due to be withdrawn in 2010 and the inclusion of new material in the Eurocode (EN 1996-1-1, Eurocode 6)[3] is not yet possible CERAM as an independent body has published a Design Guide[4] for the system. This paper introduces the guide, explains the provisions and shares the supporting test evidence. The system has been used on a number of major schemes and some feedback on the experience so far is given.

KEYWORDS: Aggregate concrete blockwork, lateral load design, bond beams

A8-5

1. A.Sc. Candidate, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, mihaljsn@mcmaster.ca
2. Professor, Center for Effective Design of Structures, Department of Civil Engineering, McMaster University, chidiac@mcmaster.ca

ABSTRACT

Concrete is the most widely used construction material, therefore reducing the environmental impact of concrete would greatly benefit the construction industry. The production of concrete, concrete blocks are no exception, requires the use of large quantities of natural resources, namely limestone, granite, shale and clay, and contributes to the production of carbon dioxide, in the manufacturing of Portland cement. Environmental benefits may be achieved by replacing a portion of the aggregate and cement with waste materials, such as glass and polymers, from postconsumer sources. It has been shown that glass can be used to replace a portion of the natural aggregate. Glass also is also being used as a supplementary cementing material. Furthermore, post-consumer polymer products, referred to as plastics, have been used as aggregate replacement in concrete. This paper provides a review of the research reported in the literature on the effects of using post consumer waste glass and plastics in concrete and concrete block production.

KEYWORDS: aggregate, cement, concrete, glass, plastic, pozzolan

C6-4

1. Sc., Structural Designer, Halcrow Yolles, Calgary, AB Canada   jason.moroz@halcrowyolles.com
2. Associate Professor, Civil Engineering Department, The University of Calgary, Calgary, AB Canada sllissel@ucalgary.ca

ABSTRACT

In order to produce structurally sound housing for developing countries, different approaches need to be taken to produce economically viable buildings. One method to produce low cost housing is the use of indigenous materials in place of conventional materials such as steel. Bamboo is a rapid-renewable plant native in many places of the world, and has many beneficial properties that make it a promising, inexpensive alternative to steel reinforcement.

This paper presents an overview of experimental testing carried out using the bamboo species arundinaria amabilis, more commonly known as tonkin cane for use as internal reinforcement in masonry shear walls. The results of tensile strength tests on the bamboo, bond strength tests between a low-cement ratio grout and the bamboo, and experimental quasi-static cyclic testing on two shear walls are presented. One wall contained the required seismic reinforcement described by the Canadian Masonry Design Code S304.01-04, while the other contained tonkin cane bamboo as internal reinforcement. These results are analyzed and discussed.

KEYWORDS: Bamboo; Cyclic; Indigenous; Low Cost; Masonry; Shear Walls

C6-3

¹ Professor Emeritus, Centre for Effective Design of Structures, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, drysdale@mcmaster.ca

² Research Engineer, McMaster University

ABSTRACT

A light-weight, oversized concrete block manufactured using saw dust as aggregate and marketed under the trade name of ENVIROBLOCK , was tested to find material and structural properties under several loading conditions. These included out-of-plane bending, in-plane shear, eccentric axial load and pure compression. Both ungrouted and fully grouted specimens were made with the fully grouted samples being either reinforced or unreinforced. The ability to use standard design practices represented in masonry design codes was confirmed with the exception of tensile bond for ungrouted construction.

KEYWORDS: compression, concrete block, environmental, grout, saw dust, shear, tension, testing, waste

A6-5