Reinforcement – CMDC https://www.canadamasonrydesigncentre.com Supporting the Masonry Design Community Thu, 29 Feb 2024 19:37:36 +0000 en-US hourly 1 https://wordpress.org/?v=6.4.3 https://www.canadamasonrydesigncentre.com/wp-content/uploads/2023/09/cropped-android-chrome-512x512-1-32x32.png Reinforcement – CMDC https://www.canadamasonrydesigncentre.com 32 32 Concordia University https://www.canadamasonrydesigncentre.com/research/concordia-university/ Mon, 13 Nov 2023 14:33:13 +0000 https://www.canadamasonrydesigncentre.com/?p=13020

CMDC has worked in collaboration with Khaled Galal from Concordia University

Supporting Innovation through Research Partnerships

Work has been conducted on the following projects:

Shear Walls with Boundary Elements

Project Summary:

Reinforced masonry shear walls are effective structural elements to resist lateral loads on buildings including wind loads and seismic loads. This research project led by Dr. Galal focuses on testing of reinforced masonry shear wall configurations to develop more economical methods of construction for buildings that are required to resist moderate earthquake loads. Focusing on the detailing of reinforcement, strategies to enhance the performance of current masonry construction methods are being developed.

This project includes testing masonry materials, of half-scale reinforced masonry shear walls (including rectangular walls, walls with boundary elements, and even partially-grouted walls), and computer modeling and analysis of the walls and of whole buildings with masonry shear walls.

In addition to developing new strategies for design and improving the seismic safety of buildings, the project also contributes to better understanding the characteristics of masonry materials in general.

Select Journal Articles:

AbdelRahman, Belal, and Khaled Galal. “Experimental investigation of axial compressive behavior of square and rectangular confined concrete-masonry structural wall boundary elements.” Engineering Structures 243 (2021): 112584.

Albutainy, Mohammed, and Khaled Galal. “Experimental investigation of reinforced concrete masonry shear walls with C-shaped masonry units boundary elements.” In Structures, vol. 34, pp. 3667-3683. Elsevier, 2021.

Hosseinzadeh, Shadman, and Khaled Galal. “Probabilistic seismic resilience quantification of a reinforced masonry shear wall system with boundary elements under bi-directional horizontal excitations.” Engineering Structures 247 (2021): 113023.

Aly, Nader, and Khaled Galal. “In-plane cyclic response of high-rise reinforced concrete masonry structural walls with boundary elements.” Engineering Structures 219 (2020): 110771.

Aly, Nader, and Khaled Galal. “Experimental investigation of axial load and detailing effects on the inelastic response of reinforced-concrete masonry structural walls with boundary elements.” Journal of Structural Engineering 146, no. 12 (2020): 04020259.

Hosseinzadeh, Shadman, and Khaled Galal. “System-level seismic resilience assessment of reinforced masonry shear wall buildings with masonry boundary elements.” In Structures, vol. 26, pp. 686-702. Elsevier, 2020.

Aly, Nader, and Khaled Galal. “Seismic performance and height limits of ductile reinforced masonry shear wall buildings with boundary elements.” Engineering Structures 190 (2019): 171-188.

Hamzeh, Layane, Ahmed Ashour, and Khaled Galal. “Development of fragility curves for reinforced-masonry structural walls with boundary elements.” Journal of Performance of Constructed Facilities 32, no. 4 (2018): 04018034.

Obaidat, Ala’T., Ahmed Ashour, and Khaled Galal. “Stress-strain behavior of C-shaped confined concrete masonry boundary elements of reinforced masonry shear walls.” Journal of Structural Engineering 144, no. 8 (2018): 04018119.

El Ezz, Ahmad Abo, and Khaled Galal. “Compression behavior of confined concrete masonry boundary elements.” Engineering Structures 132 (2017): 562-575.

Reinforced Masonry Shear Walls

Project Summary:

Reinforced masonry shear walls are effective structural elements to resist lateral loads on buildings including wind loads and seismic loads. This research project led by Dr. Galal focuses on testing of reinforced masonry shear wall configurations to develop more economical methods of construction for buildings that are required to resist moderate earthquake loads. Focusing on the detailing of reinforcement, strategies to enhance the performance of current masonry construction methods are being developed. This project includes testing masonry materials, of half-scale reinforced masonry shear walls (including rectangular walls, walls with boundary elements, and even partially-grouted walls), and computer modeling and analysis of the walls and of whole buildings with masonry shear walls. In addition to developing new strategies for design and improving the seismic safety of buildings, the project also contributes to better understanding the characteristics of masonry materials in general.

Select Journal Articles:

Elmeligy, Omar, Nader Aly, and Khaled Galal. “Sensitivity analysis of the numerical simulations of partially grouted reinforced masonry shear walls.” Engineering Structures 245 (2021): 112876.

Aly, Nader, and Khaled Galal. “Effect of ductile shear wall ratio and cross-section configuration on seismic behavior of reinforced concrete masonry shear wall buildings.” Journal of Structural Engineering 146, no. 4 (2020): 04020020.

ElDin, Hany M. Seif, Ahmed Ashour, and Khaled Galal. “Seismic performance parameters of fully grouted reinforced masonry squat shear walls.” Engineering Structures 187 (2019): 518-527.

ElDin, Hany M. Seif, Nader Aly, and Khaled Galal. “In-plane shear strength equation for fully grouted reinforced masonry shear walls.” Engineering Structures 190 (2019): 319-332.

Recent NAMC Articles:

Aly N. and Galal K. (2019, June). “Influence of Ductile Shear Wall Ratio on the Seismic Performance of Reinforced Concrete Masonry Shear Wall Buildings.” In P.B. Dillon & F.S. Fonseca (Eds.), Proceedings of the Thirteenth North American Masonry Conference. Paper presented at the 13th North American Masonry Conference, Salt Lake City, Utah (pp. 1462–1474). Longmont, CO: The Masonry Society.

Masonry Prisms

Project Summary:

Masonry prisms are essential structural elements utilized in construction to evaluate the compressive strength and other mechanical properties of masonry materials. These test specimens, constructed by bonding masonry units with mortar, replicate real-world construction conditions, ensuring the relevance of the obtained data. CSA S304 provides guidelines for the preparation, testing, and analysis of these prisms. The testing process involves subjecting the prisms to axial loads to determine compressive strength and may include shear strength tests to assess resistance to lateral forces.

In this research, masonry prisms are used to investigate the impact of fibre reinforced grout, and boundary elements built using C-shaped blocks. The resulting data contributes to the development of construction guidelines and safety standards, informing the design of durable and secure masonry structures in real-world applications. In essence, masonry prisms play a crucial role in advancing our understanding of masonry behavior and promoting the reliability of construction practices.

Recent Journal Articles:

Gouda, Omar, Ahmed Hassanein, Tarik Youssef, and Khaled Galal. “Stress-strain behaviour of masonry prisms constructed with glass fibre-reinforced grout.” Construction and Building Materials 267 (2021): 120984.

AbdelRahman, Belal, and Khaled Galal. “Influence of pre-wetting, non-shrink grout, and scaling on the compressive strength of grouted concrete masonry prisms.” Construction and Building Materials 241 (2020): 117985.

Masonry Columns Strengthened by FRP

Project Summary:

Research on masonry columns strengthened by Fiber-Reinforced Polymer (FRP) composites aims to enhance the load-carrying capacity and ductility of existing structures. This involves applying high-strength fibers embedded in a polymer matrix externally to masonry columns, particularly beneficial for retrofitting older structures or improving original design capacities. The test matrix was designed to measure the effect of the presence of longitudinal steel reinforcement in the columns on the compressive strength of FRP-confined concrete masonry.

As the demand for sustainable retrofitting solutions increases, research in this area plays a pivotal role in advancing innovative techniques for strengthening masonry columns, ensuring resilience in diverse environmental and loading conditions.

Recent NAMC Articles:

Alotaibi K. and Galal K. (2019, June). “Compressive Strength of FRP-Confined Concrete Masonry With and Without Longitudinal Steel Reinforcement.” In P.B. Dillon & F.S. Fonseca (Eds.), Proceedings of the Thirteenth North American Masonry Conference. Paper presented at the 13th North American Masonry Conference, Salt Lake City, Utah (pp. 1523–1529). Longmont, CO: The Masonry Society

Select Journal Articles:

El-Sokkary, Hossam, and Khaled Galal. “Performance of eccentrically loaded reinforced-concrete masonry columns strengthened using FRP wraps.” Journal of Composites for Construction 23, no. 5 (2019): 04019032.

Alotaibi, Khalid Saqer, and Khaled Galal. “Experimental study of CFRP-confined reinforced concrete masonry columns tested under concentric and eccentric loading.” Composites Part B: Engineering 155 (2018): 257-271.

Alotaibi, Khalid Saqer, and Khaled Galal. “Axial compressive behavior of grouted concrete block masonry columns confined by CFRP jackets.” Composites Part B: Engineering 114 (2017): 467-479

Select Theses and HQP: :

Khalid Alotaibi: https://spectrum.library.concordia.ca/id/eprint/984232/

]]> Why does MASS use unreinforced analysis for a design with reinforcement? https://www.canadamasonrydesigncentre.com/software/why-does-mass-use-unreinforced-analysis-for-a-design-with-reinforcement/ Mon, 06 Mar 2017 16:04:03 +0000 http://www.canadamasonrydesigncentre.com/?p=5832 Adding steel to a wall design does not necessarily mean that the steel is being used. How to avoid adding steel that offers no benefit

The CSA S304-14 divides masonry wall design into two separate chapters depending on whether or not the wall is reinforced. Chapter 7 and chapter 10 govern the design of unreinforced walls and reinforced walls respectively. Since steel cannot be used in compression without being laterally tied to prevent buckling, it is ignored for all design calculations which opens up a “grey” area. Walls can be vertically reinforced with the steel doing nothing from a capacity and moment resisting perspective if the bars are not in tension. It is these cases where the steel is ignored and the wall is designed as if it were unreinforced.

How to tell when a wall is designed with the reinforcement ignored

For a bar to be included, it must be further away than the neutral axis from the extreme compression edge of a wall and therefore in tension. Since the neutral axis location is a function of axial load (and the area of masonry required for the compression block to equal the axial load plus tensile force in the steel), there is a break even point where any marginal increase in axial load shifts the neutral axis beyond the depth of reinforcement. MASS solves for this point where the steel is no longer in tension and saves the corresponding axial loads and moment as Mtension and Ptension. For example, bars placed in the middle of a 20cm unit (thickness of 190mm) are 95mm away from the compression edge. Axial loads that result in a neutral axis, or c, location of 95mm or higher ignore the effects of steel in the design.

No. 15 bars placed at 1200mm in a partially grouted 20cm, 15MPa unit

Conversely, axial loads resulting in a c value that is less than d result in designs which include the added effects of reinforcement.

Skill testing question

Is it possible to have a wall that both ignores and includes the effects of reinforcement at the same time but for different load cases?

Decide for yourself and then click to expand the answer

Yes! While the envelope curve itself is constant for a cross section, independent of loading, some load cases can fall above and others below the axial load at which reinforcement is no longer in tension, Ptension. This actually happens more frequently than you might think. The critical load case may be the one with the highest factored lateral load with a lower axial load (0.9D instead of 1.25D for example). While all of the results in MASS (or hand calculations) rely upon the steel being in tension, a non-critical load case (let’s say, 1.4D) may be above this threshold.

Where to check this using MASS

This can be checked in MASS in two places. The first is at the bottom of the Simplified Moment Results, where there a table showing how MASS arrives at a total factored moment for each load case. The Simplified Moment Results table corresponds to the example shown in the interaction diagrams above.

All load cases that result in a neutral axis location less than d (95mm in this case) use the reinforcement in tension. From looking at the table above, reinforced analysis is used for load cases 1, 3, 7, and 9.

The other place to find this information in MASS is on the actual interaction diagram drawing. Each load case can be clicked on to reveal the following information:

  • Mf,p – Primary factored moment (kN*m)
  • Mf,tot – Total factored moment (kN*m)
  • Mr – Moment resistance (kN*m)
  • Pf – Factored axial load (kN)
  • c – Neutral axis location (mm)

Load combination 7 selected displaying corresponding summary information.

“Am I benefiting by adding steel to this wall?”

While a design may be designed as reinforced, where the steel is in tension and adds to a wall’s moment resistance, that does not mean that the steel is needed. Looking at the interaction diagram above, and where each load combinations lies to the region of the wall can offer insight into how the wall is behaving and which mechanism governs its failure at ultimate conditions.

Cracking restrictions based on limiting eccentricity of an unreinforced wall with the envelope curve of a reinforced wall.

The main benefit of vertical steel to the moment capacity of a wall is in the blue region of the figure above, where otherwise the wall would not be permitted to crack and rely on the tensile strength of masonry. Generally, load combinations with high lateral loads and lower axial loads fall within that region and benefit from the added steel. The example used in this post highlights an instance where the lateral loading is relatively small (Ex. low net internal wind pressure) and the reinforcement is not needed to satisfy the wall’s capacity requirements.

As written about in another post, there can be other reasons why MASS is adding reinforcement to a wall. However, it should be noted that by starting with the default masonry unit and reinforcement selections, MASS will first return a successful unreinforced design and only after the disabling the unreinforced selections will MASS add “unnecessary” steel to a wall design.

There are perfectly valid reasons to add steel to the wall design in this example that are outside the scope of a MASS wall module such as when the wall is acting in a system with other reinforced walls. The important thing is that the designer fully understands why the software returns the results that it does and what the reasons are for doing so.

As always, feel free to contact us if you have any questions at all. CMDC is the authorized service provider for the MASS software which is a joint effort of between CCMPA and CMDC.

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