Engineering for Top-Down Construction
Simplifying Excavation and Building Construction
Construction typically relies on the bottom-up method. This means builders start at the basement level and sequentially move their way up to the top of the structure. But construction and deep excavation projects in crowded urban areas with neighboring buildings along lot lines present numerous challenges. When construction time and space are an issue, FNA can reduce excavation costs and times and eliminate the need for underpinning by designing engineering plans that use the top-down construction method.
Top-down excavation and construction allow substructures and superstructures to be constructed simultaneously. FNA’s expertise ensures the sufficient vertical load capacities of walls and proper support of internal columns for the permanent structure during construction. Our proven multidisciplinary capabilities with complicated jobs involving MTA structures, old buildings, and tight spaces have built our reputation as the premier source of engineering services. Because of this, we’ve become the go-to source for developers and contractors looking for constructible, creative, and cost-effective solutions.
FNA typically relies on the top-down construction method for tall buildings with deep basements and structures below the ground floor, like parking garages, subway stations, and underpasses. Excavation projects where tieback or anchor installation is not practical or when sites must minimize soil movement are additional applications of top-down construction.
Along with significant time and money savings, the top-down construction method provides other advantages, including:
After FNA designs the plans, the top-down excavation method begins by installing retaining walls followed by load-bearing elements needed to carry the permanent structure. Before basement excavation begins, basement columns, usually made of steel columns, are constructed. Next, they’re placed on load-bearing features like concrete piles and diaphragm walls.
The first stage of top-down excavation is then ready to begin. Floor slabs for the first basement level are cast with an opening left for excavation equipment to be lowered and soil, rock, and other materials to be removed. This process repeats until you reach the bottom of the structure and the foundation slab is constructed, thus completing the basement floor. From there, the superstructure is built to completion.
(Waiting on Client to provide Case Study) Praesent sapien massa, convallis a pellentesque nec, egestas non nisi. Pellentesque in ipsum id orci porta dapibus. Nulla porttitor accumsan tincidunt. Pellentesque in ipsum id orci porta dapibus. Donec rutrum congue leo eget malesuada. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur arcu erat, accumsan id imperdiet et, porttitor at sem.
Curabitur non nulla sit amet nisl tempus convallis quis ac lectus. Praesent sapien massa, convallis a pellentesque nec, egestas non nisi. Cras ultricies ligula sed magna dictum porta. Vivamus magna justo, lacinia eget consectetur sed, convallis at tellus. Donec rutrum congue leo eget malesuada. Donec sollicitudin molestie malesuada. Pellentesque in ipsum id orci porta dapibus.
Learn the role FNA played and the solutions we provided for some of the country’s most challenging and well-known projects.