Geostructural Engineering and Design
Geostructural engineering requires the collective expertise from geotechnical, structural, and construction disciplines to analyze the complex interaction between earth, water, and structure. The design of excavation support systems, earth retention systems, foundations, and some types of ground improvement are common examples of geostructural systems. These systems are frequently on the critical path of a construction project and needed to fix a problem (e.g., landslide stabilization). Additionally, they often involve a higher degree of risk due to inherent limitations in geotechnical site characterization, uncertainty in analytical methods, and the potential consequences of unsatisfactory performance. As a result, getting it right is fundamental to a project’s success.
Development of new and existing sites often requires below-grade support of excavation to facilitate construction underground. A variety of support of excavation alternatives are available, including groundwater cut-off systems, with the most efficient and appropriate system a function of site and project-specific constraints and requirements. Support of excavation can be temporary, to facilitate construction of the permanent structure, or permanent, in which the support of excavation becomes incorporated as part of the permanent structure. Excavation support systems and walls include:
- Internally Braced
- Tied-back
- Soldier Pile and Lagging Walls
- Soil Nail Walls
- Rock Anchors
- Sheetpile Wall
- Secant Pile Walls
- Tangent Pile Walls
- Soil Mixed Walls
- Diaphragm Walls
- Mechanically Stabilized Earth (MSE) Walls
- Conventional Concrete Retaining Walls
Many of today’s developments require ground improvement for underground construction or acceptable performance of the foundation and structure. S&ME has extensive ground improvement design experience stabilizing subgrades for foundation support, but also groundwater control and excavation/slope stabilization, including:
- Deep Soil Mixing (DSM)
- Jet Grouting
- Slope Stabilization
- Compaction Grouting
- Permeation Grouting
- Stone Columns
- Rigid Inclusions
- Seepage Cutoff Walls
Shallow and deep foundation system design for structures ranging from bridges and walls to industrial developments is a service routinely performed by S&ME. We are frequently asked to design foundation systems for the retrofit or repurposing of existing facilities where access is difficult and risk to critical existing elements is a primary project concern. Some of the systems we design are:
- Driven Piles
- Drilled shafts
- Augercast piles
- Micropiles
- Tiedowns
- Footings and mat foundations
- Wet excavation bottom plugs (seals)
- Crane pads and work platforms
Some geotechnical problems cannot be solved using standard analysis techniques due to complexity and/or variability of the subsurface conditions and/or structure. Numerical modeling can be used to define the critical elements of the design, conduct stress and displacement analysis, as well as evaluate potential design elements in both two and three-dimensional settings. S&ME utilizes finite difference modeling to analyze the anticipated performance and displacement of composite soil-structure systems.
Geosynthetics may play a major role in some projects. Components include liners, geotextile filters, soil stabilizing grids and synthetic drainage materials. Geosynthetics are increasingly specified for use in containment and retention structures, subgrades, and earthen structure stabilization.
S&ME can design the structure, detail the components, and provide specifications for construction. We can also provide on-site observation to ensure that construction be consistent with the design intent. Our staff can address unfavorable conditions encountered in the field by developing and applying reasonable and practical approaches to investigate and characterize the conditions encountered. We are fully familiar and experienced with the practical application of analytical processes and tools, and can analyze the influence of altered conditions on performance of the system. We can then recommend measures for remediating the engineering characteristics of the soil and rock at a specific site through soil and rock improvement or supplementing the support design.