Before the construction of any project begins, the contractor must have a good understanding of the foundation system and the underlying soil conditions. As part of the preconstruction process, the engineers will perform a variety of tests and investigations to assess the ground conditions as well as any subsurface conditions that may affect the design and construction of the building’s foundations.
The Differences Between Shallow and Deep Foundations
Shallow foundations are often referred to as footings, spread/strip footings, or mats. They are generally considered shallow when the depth(D) to the width(B) ratio (D/B) of the footing is ≤ 1.= but may be more. For areas exposed to frost, they are designed to be placed minimally at the regional frost depth which is usually defined in local codes.
Deep foundations are often referred to as piles, drilled piers, or caissons. Foundations are generally considered deep when the depth(D) to width(B) ratio (D/B) is ≥ 4+ and can extend as far as 300 feet below ground level, or more. When designing foundations, the engineers will assess both the soil conditions and the size and weight of the structure that they are building. For small, light to moderate weight structures, a smaller foundation constructed closer to the surface is usually all that is required to support the weight given the right soil conditions. If they are not, then some type of ground improvement or a deep foundation system is required.
Shallow foundations are usually constructed as individual footings or as isolated footings. These are less expensive and easier to construct and reduce the amount of time needed to complete the building. Other types of shallow foundations include combined footings, strip foundations, and raft or mat foundations. These types of foundations are used when the geographical location and soil conditions dictate a more versatile foundation.
Soil testing in Monmouth County, NJ is an important part of the construction planning process as the soil conditions vary from sand to clay. Each type of soil requires a specific foundation layout and strength, so a thorough assessment must be made of the underlying soil conditions before construction takes place.
Deep foundations are generally required for heavy, multi-story buildings or other structures, or when the soil conditions are too weak to support the structure. These foundations are constructed using piles or drilled shafts, also known as caissons. The depth of the foundation is dependent on the subsurface conditions, types of soil and rock, as well as the size and weight of the structure.
The Preconstruction Meeting
A pre-construction meeting provides an opportunity for developers or owners and the professional team to sit down and discuss the specifics of the construction. The engineers will highlight areas of concern as well as make suggestions and provide solutions for the problems that may be present on site.
This meeting helps define the scope of the project and allows you to decide whether the project is feasible or not. It is also an opportunity to assess the professional team to see how well they work together and gauge their expertise.
Daily Field Inspection & Testing
Once a decision is made regarding the construction cost, process, and timeline, regular inspections are scheduled to check on the construction progress.
Foundation testing and consulting in Philadelphia are carried out to satisfy both the client’s building requirements as well those of the Department of Licenses and Inspection.
A site inspection checklist can be used to ensure that all areas of concern are covered and that any changing conditions on site are brought to the attention of the design engineers. The general contractor will often encounter conditions when excavating that require an engineer’s input or further investigation. For more information and advice, contact the professional team at Earth Engineering Inc. today.