FORTES, ERNESTO SILVA1; CANATO, RICARDO LUIS2; PARSEKIAN, GUILHERME ARIS3
(1)Master, PhD Student, Federal University of São Carlos, Civil Engineering Department, ernestofortes@hotmail.com
(2)Master Student, Federal University of São Carlos, Civil Engineering Department, ricluiz@ufscar.br
(3)PhD, Professor, Federal University of São Carlos, Civil Engineering Department, parsekian@ufscar.br
The modern use of structural masonry when engineered-designed walls replace empirically built massive walls is only possible if the quality of the execution and of the materials is also certified.
Around the world different building types are preferable and more economical to be constructed with masonry—from low-rise to high-rise residential buildings with a higher demand on compressing strength or for one-story buildings, such as schools and warehouses, when the compression strength is not so critical. Thus, being masonry a compression-type material, the control of its compression strength is often required by building codes.
In some regions the jobsite control may be based on the block, mortar and grout strength, being the prism strength conservatively estimated from these results. In others, particularly those where buildings have a higher compression strength demand, testing of prisms from the actual jobsite may be required. Also, some codes may allow the average strength to be used and therefore controlled while other codes may require a strength value at 95%, or sometimes 90% confidence level.
This work aim is to present a comparative analysis on the specification for controlling the compressive strength of masonry. The analysis will include specifications from the European, North American, Canadian and Brazilian codes. More specifically, this work will assess and compare the required specimens type (block, prism, mortar, and grout), number of samples, reference value (average or characteristic) and how the masonry specified strength is calculated.
As conclusion, the Brazilian standard specifies prisms testing, as the main focus to control the masonry jobsite resistance, with sufficient samples to obtain the characteristic value. In contrast, in most cases, international standards specify only blocks testing, but using conservative prism/block correlations in projects where many times the compressive strength is not decisive (low buildings subject to predominantly lateral force).
Keywords: Quality Control, Building Code, Compressive strength, Specifications