Once the slab is designed, the LDP is required to show locations and details of all reinforcement, including all lap splices.

The LDP can also rely on past experience with similar slabs. Since the design requirements for non-structural slabs-on-ground are specifically excluded from the ACI 318-19 building code, section 1.4.8, the LDP typically uses design guides prepared by ACI, CRSI, WRI and so on. The WWR is used only for control of concrete slab shrinkage cracks. The slab thickness and proper preparation of the subgrade provides that. The WWR in the slab actually contributes very little to its load-carrying capacity. Examples of non-structural slabs include industrial, commercial, and residential slabs intended to carry material loads, storage rack loads, and any static or moving loads from equipment and vehicles. By definition, such slabs are supported by the ground with the main purpose of transmitting all applied loads through bearing onto a properly prepared subgrade. The non-structural slab-on-ground on this project was probably designed per ACI 360: Design of Slabs-on-Ground. We believe the as-placed WWR is likely to be accepted by the LDP with little or no rework required. Since the WWR lap splice requirements are not available in the construction documents, it appears the inspector has mistakenly referred to Chapter 25 or the ACI 318 building code as a default to support his decision. How can we prove our installation is fit for purpose and acceptable?” Neither the structural construction documents nor the WWR shop drawings indicated lap splices.

While ACI 318-19 does call for the lap length cited by the inspector, we don’t agree with his interpretation. The inspector is citing ACI 318-19, section 25.5.4, which covers plain wire WWR tension lap splices for structural slabs.

The project inspector has rejected the laps, saying they must be one square plus 2 inches, or 8 inches total, minimum. We installed the WWR using a lap splice of one square overlap, or 6 inches. Reinforcing for the slab is plain welded-wire mesh (WWR 6圆). “We have a project featuring a 6-inch thick concrete slab-on-ground over an 85,000 SF footprint of prepared subgrade. Jim Klinger, Concrete Construction Specialist, The Voice Newsletter, January 2021 Safety Training & Assessment Recognition.

Define concrete tension lap splice