Foundation, Concrete and Earthquake Engineering: February 2010

FIRE BARRIERS

Fire barriers must be made of materials that are permitted by the building type of construction and fire-resistance-rated glazing, when tested in accordance with ASTM E 119 shall comply with this section. They have to be labeled or show some type of identification, provided by an approved agency that has the name of the manufacturer, the test standard and the identifier that includes the fire-resistance rating. Exit enclosures, exit passageways, to include horizontal exits, all must comply with the code book.

When outside walls are part of a required fire-rated shaft or exit enclosure they have to be in accordance with the code. Fire barriers must extend from the top of the floor/ceiling assembly below to the bottom of the floor or roof slab or deck above and be securely attached.

Fire barriers must also be continuous through concealed spaces, such as the space above a suspended ceiling. All supporting construction must be protected to allow the required fire rating of the fire barrier supports. Hollow vertical spaces within a fire barrier must be fire blocked at every floor level except that shaft enclosures are allowed to end at a top enclosure when complying with this section.

All outside walls that are used as a part of a required fire-rating enclosure or separation have to comply with this section except for outside walls that are in accordance with code exceptions. Openings in a fire barrier will be protected and will be limited to a maximum aggregate width of 25 percent of the length of the wall having a maximum area of any single opening not being more than 156 square feet. This does apply to openings that have adjoining fire sprinklers throughout and the opening assembly has been tested with ASTM E 119, fire doors serving as an exit.

MEZZANINES (IBC-09)

Mezzanines that conform to this section can be considered a portion of the story. They cannot, however, be counted as either the building area or the number of stories as regulated by this section. The area of the mezzanine must be included in determining the fire area. The clear floor height of your mezzanine cannot be less than 7 feet.

The total area of a mezzanine within a room is not allowed to be over one third of the floor area of the room or the space that they are in. You also cannot include the enclosed part of the room to determine the floor area where the mezzanine is located. When determining the allowable mezzanine area, the area of the mezzanine cannot be included in the floor area except for the following:

A. The total area of mezzanines in buildings and structures that are Type I or II (see Occupancy Classifications:IBC-09) for special industrial occupancies in accordance with this chapter cannot be more than two-thirds of the area in the room.

B. The total area of mezzanines in buildings and structures that are Type I or II cannot be more than one-half of the area of the room in buildings and structures that have an approved sprinkler system throughout. The sprinkler system has to be in accordance with code requirements and an approved emergency voice/alarm communication system.

Mezzanines are no different when talking about exits and exit routes. Each occupant of a mezzanine must have access to at least two exits where the common path of exit travel is over the limits. If the exit from your mezzanine is a stairway, the maximum travel distance must include the distance traveled on the stairway measured in the plane of the tread nosing.

Accessible means of exits must be provided, as well as a single means of exit. If a building or structure has a mezzanine it has to be open and no obstructions are allowed in the room where the mezzanine is located, except for walls that are not more than 42 inches high, columns, and posts.

There are five exceptions to this code, and they are as follows:

1. Mezzanines or portions that are of concern are not required to be open, provided that the occupant load does not go over 10 persons.

2. Mezzanines or portions that are of concern are not required to be open to the room if at least one of the exits provides direct access to an exit from the mezzanine level.

3. Mezzanines are not required to be open to the room, provided that the total floor area of the enclosed space does not go over 10 percent of the area.

4. In industrial facilities, mezzanines used for control equipment are allowed to be glazed on all sides.

5. In Groups H and I occupancies that are no more than two stories in height above grade plane and equipped with an automatic sprinkler, a mezzanine having two or more exits is not required to be open to the room in which the mezzanine is located.

MICROPILES (IBC-09)

Micropiles are 12-inch-diameter or less bored, grouted-in-place piles incorporating steel pipe (casing) and/or steel reinforcement. There has been a change in the code regarding micropiles and in this section I have covered all of these changes. Keep your eyes open for any details that pertain to your construction or building needs and as always ask your local building official to clarify any questions that you may have regarding this code.

Micropiles must have a grouted section reinforced with steel pipe or steel reinforcing. Micropiles develop their load-carrying capacity through soil, bedrock, or a combination of soil and bedrock. The full length of the micropile must contain either a steel pipe or steel reinforcement. One of the materials used with micropiles is grout.

Grout must have a 28-day specified compressive strength no less than 4,000 psi. As with all piles, micropiles too must be reinforced. For piles or portions of piles grouted inside a temporary or permanent casing or inside a hole drilled into bedrock, the steel pipe or reinforcement must be designed to carry at least 40 percent of the design compression load.

You can use rotary or percussive drilling as a method, with or without casing, to form a hole for the pile. The pile must be grouted using a fluid cement grout and pumped through a tremie pipe that extends to the bottom of the pile until the grout comes back up to the top. There are eight requirements of this code that must be applied to specific installation methods:

A. For piles grouted inside a temporary casing, the reinforcing steel must be inserted prior to withdrawal of the casing.

B. The casing must be withdrawn in a controlled manner with the grout level maintained at the top of the pile to ensure that the grout completely fills the drill hole.

C. Make sure you monitor the grout level inside the casing when you are withdrawing the casing so you can see that there is nothing obstructing the flow of the grout.

D. You must verify the design diameter of the drill hole for a pile that is grouted in an open drill hole in soil without temporary casing.

E. By using a suitable means for piles designed for end bearing you will be verifying that the bearing surface is properly cleaned prior to grouting.

F. Subsequent piles cannot be drilled near piles that have been grouted until the grout has had enough time to harden.

G. You must grout piles as soon as possible after you have completed drilling.

H. For piles designed with casing full length, the casing must be pulled back to the top of the bond zone and reinserted to verify grout coverage outside the casing.