Testing In-Wall Compressive Strength Northampton MA

Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: October 1, 1992

Our firm is adding a partial second story to an old warehouse to convert it to an office building. The foundation and soil conditions make the project possible, but how can I determine the compressive strength of the existing masonry? How many areas should I test? What methods are most cost effective?

I know four methods for determining the compressive strength of existing walls. The first is to remove a section from the wall and send it for laboratory testing per ASTM E 447. There are some problems with this approach, however. Physically removing samples from the wall affects its appearance. Depending on the building's age, matching the color and texture of the masonry units removed may be nearly impossible. Also, samples may be damaged during removal or shipping, especially if the wall has multiple wythes. A second method is to make two vertical cuts entirely through the wall thickness and remove some of the masonry between these cuts. An in-place compression test can be performed using a hydraulic ram. As with the previous test method, the wall will be damaged by this testing and it may be difficult to perform in multi-wythe systems. Because the test is performed in place, however, samples will not be disturbed in shipping. The third method involves removing masonry units and samples of the mortar and estimating the compressive strength. The masonry units are tested in accordance with ASTM C 6...

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