Urm Building Retrofitting With Concrete Wall

Diaphragm repair and strengthening.

Urm building retrofitting with concrete wall.

Th e urm problem in jurisdictions that are now eff ectively enforcing the current building code essentially the latest edition of the international building code the ibc is due to those buildings that were built before recent model code seismic pro. Abstract there are many complex considerations when seeking to seismically retrofit unreinforced masonry urm buildings. Wall repair and strengthening. The walls of a concrete tilt up building can weigh between 100 000 and 300 000 pounds.

The code requires some 8 000 urm buildings to be retrofitted vacated or demolished. Shear walls or concrete overlay walls are often installed over the inside face of existing walls and epoxy doweled to the brick. Earthquake retrofitting services for unreinforced masonry buildings urm unreinforced masonry buildings are especially vulnerable to earthquakes. Preventing the collapse of the walls particularly load bearing walls is critical in urm buildings.

Steel plates with headed studs are positioned into the forms prior to pouring the concrete to establish viable connection points that secure the walls to the foundation and the roof trusses to hold them in place. Buildings built of unreinforced masonry urm brick hollow clay tiles stone concrete blocks or adobe are very likely to be damaged in earthquakes because the mortar holding the masonry together may not be strong enough to resist earthquake forces. Or adding a fiber composite layer epoxy embedded fiberglass mesh. An unreinforced masonry building or umb urm building is a type of building where load bearing walls non load bearing walls or other structures such as chimneys are made of brick cinderblock tiles adobe or other masonry material that is not braced by reinforcing material such as rebar in a concrete or cinderblock.

2 3 wall anchorage. Concrete or shotcrete shear walls are a commonly used seismic retrofit technique. All masonry should be reinforced. And adding shear elements.

Retrofit construction of urm buildings. A lot of damage to urm buildings can be attributed to parapet failures when a seismic event occurs. The damage can occur not only to the building itself but to nearby buildings and poses a major risk to life safety. Developing successful risk reduction programs states more than any other kind of construction this type of building can be singled out as being seismically vulnerable.

In fact the fema report unreinforced masonry buildings and earthquakes. Bracing the parapets is a must when evaluating the needed retrofitting of a urm building. Strength requirements need to be evaluated and the intrinsic strength of. This entails strengthening the walls through various methods such as adding strongbacks or secondary support members to the wall.

That this existing urm building stock presents a problem with respect to earth quake risk. Similar to steel frame schemes the existing brick provides no resistance to seismic forces and the new concrete resists all loads. Experience with thousands of urm buildings has identified four major aspects of seismic retrofitting. Adding shotcrete bonded to the urm wall.