What is a Site Class D?

What is a Site Class D?

Site classes A and B correspond to hard rock and rock, Site Class C corresponds to soft rock and very stiff / very dense soil, and Site Classes D and E correspond to stiff soil and soft soil. A sixth site class, F, is defined for soils requiring site-specific evaluations.

What is seismic site classification?

The Site Class is based on the average conditions present within 100 feet of the ground surface, and are designated as A-F, with hard rock, considered an ‘A,’ down to potentially collapsible soils, which get an ‘F. ‘ The Site Classification is based on shear wave velocity.

What is a site class?

The Site Class Definition quantifies the soil’s propensity to amplify, or in some cases decrease, surface ground motion propagating from underlying rock. The Site Class Definition is also used by designers to determine the Seismic Performance Zone for a structure (3.10. 6).

What are the seismic design categories?

What is a Seismic Design Category

• Seismic Design Category A – Corresponds to buildings in areas where expected ground shaking will be minor.
• Seismic Design Category B – Corresponds to buildings of Occupancy Groups I,II and III where expected ground shaking will be moderate.

What is Seismic Site Class C?

Sites consisting predominately of very dense glacial tills, sands, gravels, and soil sites with very shallow rock often qualify as Site Class C. When shallow foundations are allowed for a building on a soil site, Site Classes C and D are generally applicable, with Site Class D being more common.

What is class E soil?

E Class soil type and slabs This is the most extreme soil type and simply means this soil has a higher level of movement. Although E class slabs are the most expensive, the good news is your home will be sitting on a very strong slab and foundation!

How is seismic design category determined?

How is the Seismic Design Category Determined? Three parameters determine the SDC: geographic location, underlying soils, and building use. First, geographic location drives SDC. Many regions have a low seismicity.

What is soil Class D?

Group D soils are clay loam, silty clay loam, sandy clay, silty clay or clay. This HSG has the highest runoff potential.

What does seismic design category E mean?

Buildings in Seismic Design Category E shall be designed to resist seismic loads in accordance with the International Building Code, except when the seismic design category is reclassified to a lower seismic design category in accordance with Section R301.

What is SS and S1 seismic values?

Ss: Spectral acceleration parameter at short periods corresponding to the mapped maximum considered earthquake. S1: Spectral acceleration parameter at a period of 1 sec corresponding to the mapped maximum considered earthquake.

How are seismic site classes determined?

To obtain the seismic site class, the average shear wave velocity and average SPT ‘N’ values within the upper 30 m of the soil profile is calculated (NBC User’s Guide 2006). The average shear wave velocity is 373 m/s and average SPT ‘N’ value is 14.

What is a Class M site?

Class “M”: a moderately reactive clay. We see this site classification about 35% of the time. Ground movement isn’t ‘too bad’ and house slabs can easily be designed for this soil. Ground surface can move vertically between 20mm and 40mm between wet and dry conditions (seasons).