- The MSJC 1999 Code requires the inspection of masonry walls. How much inspection is required?
The allowable values for masonry permitted by the Code only apply if the quality of the completed masonry meets or exceeds the requirements listed in the MSJC 1999 Code and Specification. A quality assurance program must be defined in the contract documents. Ultimately, it is the designer’s responsibility to establish a reasonable quality assurance program based on the special requirements of the project. Section 1.14 of the Code and Section 1.6 of the Specification set minimum requirements for a quality assurance program.
The quality assurance programs depend on whether or not the structure is considered an essential facility, as defined by ASCE 7. Essential facilities have greater requirements for quality assurance than nonessential facilities.
The requirements for the quality assurance program also are based on whether the masonry has been designed using engineered requirements, which are listed in Chapters 2 and 4 of this document; or if the walls were designed using empirical or prescriptive methods described in Chapters 5, 6, and 7. Chapters 2 and 4 show allowable stress design and pre-stressed masonry, respectively. Chapters 5, 6, and 7 show empirical design of masonry, veneer, and glass unit masonry.
The minimum quality assurance program for masonry walls in non-essential facilities designed by using the empirical or prescriptive methods includes primarily the verification that the contractor has complied with the approved submittals. These submittals should be provided for the materials used in the masonry construction to indicate that these products meet the contract requirements. This requirement is the minimum. Consider having a qualified individual perform inspections during construction to verify proper filling of mortar joints and to verify proper mixing of mortar at the jobsite. In essential facilities designed by empirical methods, or where non-essential facilities are designed according to engineering methods, a greater level of quality assurance is required. In those cases, the minimum test submittals include verification of f’m prior to construction of the masonry walls, in addition to submittal review. The f’m is determined either by the unit strength method, which uses Table 1 in the Specification and the tested values for the compressive strength of the units along with the mortar type, or by the prism test method, which determines the compressive strength by testing three prisms per ASTM C1314.
The program also requires that during the construction of the masonry walls there will be some verification of proportions of the site-prepared mortar, the construction of the mortar joints, and the location of reinforcement and connectors. Prior to grouting, the inspector should verify that the grout space, the placing of reinforcement and connectors, proportions of site-prepared grout, and the construction of the mortar joints are in compliance with the project compliance. The inspector should also verify that the grout placement is in compliance with the project requirements, observe the preparation of grout and mortar, and verify compliance with any required inspection provisions in the contract document and the approved submittals that would go beyond the quality assurance listed in the code.
The minimum quality assurance programs for essential facilities designed using engineered methods are the most restrictive. In addition to verifying that the submittals are in compliance with the contract document, there must be a verification of f’m both prior to construction and for every 5000 square feet of masonry during construction.
There also should be verification of the proportions of the materials in mortar and grout as delivered to the site. From the beginning of the masonry construction and continuously during the construction, the inspector must verify the proportions of the site-mixed mortar and grout, the placement of masonry units, the construction of the mortar joints, the placing of reinforcement and connectors, the grout space prior to grouting, and the placement of grout. The inspector also observes the preparation of grout and mortar specimens and verifies compliance with any required conditions in the contract documents.