Is smaller mesh always better in Finite Element Analysis modeling of concrete mat foundations and slabs on grade?? Do higher moments produce more reinforcement area? Sure! but what about the total area I need for my mat slab? Can spMats produce answer to all these questions with speed and accuracy? Read the rest of this article!

When creating analytical models for design of foundation systems it is not always possible to achieve square elements with the best possible aspect ratio of 1. In this article we examined and report the findings when using a range of aspect ratios to determine any loss of computational accuracy in model results. Recommendations for spMats users are also provided.

Pile cap foundations are widely designed using helpful guides such as the CRSI handbook or PCA notes. Finite elements programs such as spMats provide simple and quick alternatives to the limited range provided in traditional guides. Quick iterations inform the engineer about the sensitivity of the solution to various parameters and simply identify the critical or governing ones. In this article the impact of the pile stiffness and pile distribution is investigated as part of the overall pile cap behavior.

Corn Products International is replacing a worn-out coal-fired power plant with a building a state-of-the-art power plant that will burn high-sulfur Illinois coal and meet all current emissions requirements. Corn Products use PCAMats to design a 4.5 foot thick reinforced mat slab consisting of 3819 cubic yards of concrete.

In structural mat foundations and slabs on grade, construction joints are typically required to transfer vertical shear force between adjacent concrete placements. Transfer of moments across the joint may or may not be required. There are two possible ways to model a construction joints in pcaMats to analyze and design a concrete foundation where only shear is transferred and moment is not.

Soil bearing capacity, soil compressibility, and soil modulus of subgrade reaction are various measures of strength-deformation properties of soil. The allowable soil bearing capacity is the maximum pressure that can be permitted on foundation soil with adequate safety against soil rupture or excessive settlement. Another soil characteristic, compressibility of cohesive soils, determines the amount of long-term settlement under load.

An existing L-shaped foundation slab (supported by Soil 1) will undergo expansion (supported by Soil 2). On the expansion side, the soil subgrade modulus is 100 kcf because the contractor could not match the soil properties under the existing foundation slab, which is 200 kcf. spMats v8.10 software program is utilized to investigate the impact of the dissimilar soils on the alculated bearing pressure for the combined foundation as well as other design parameters such as displacement, bending moments, and required reinforcement.

Ground supported slabs in industrial and residential floors are frequently designed with a single layer of reinforcement. Such slabs are referred to as membrane slabs, floating slabs, or filler slabs and range in thickness from as little as 4 to 8 inches depending on the supported loads. In warehouses and storage facilities such slabs are subjected to concentrated point loads from storage rack posts or forklift wheel loads.

Ground supported slabs in industrial and residential floors may be specified with fiber reinforcement in lieu of a single layer of reinforcing or welded wire fabric. Fiber reinforced concrete (FRC) slabs are referred to as membrane slabs, floating slabs, or filler slabs and range in thickness from as little as 4" to 8" depending on the supported loads. In warehouses and storage facilities such slabs may be subjected to concentrated point loads from storage rack posts or forklift wheel loads. FRC can be used with conventional reinforcing as a hybrid system in foundations and walls to meet construction quality and schedule.

Ground supported slabs with light loading and residential flooring are frequently designed without reinforcing (unreinforced). Such plain concrete slabs are referred to as membrane, floating, or filler slabs and range in thickness from as little as 4" to 8" depending on the supported loads. In warehouses and storage facilities such slabs are subjected to concentrated point loads from storage rack posts or forklift wheel loads.

Structural engineers routinely ask us about the influence of mesh density on the results obtained from spMats models. In any Finite Element Analysis (FEA), individual finite elements can be visualized as small pieces of a structure and particular arrangements of these elements is known as a mesh. Mesh density in FEA is defined as the number of elements used in modeling a given structure.

Footing design requires load factors for calculation of pressure distribution and determination of soil contact area for all service and ultimate load combinations. Major differences between service and ultimate design conditions can exist. spMats Program users often ask about this and possible uplift? Dr. Jim Wight and ACI-318 members help clarify this issue in a Q&A from an issue of CI.