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<br />I <br />c <br /> <br />c~ <br /> <br />(, <br /> <br />Cross Construction Services, Inc. <br />@ 2011 DEMOLITION SAFETY PLAN <br />CROSS CONSTRUCTION SERVICES. INC. <br /> <br />2. Categories 2- Like Category 1, but the tendons are left ungrouted. This type of <br />construction can sometimes be recognized from the access points that will have been <br />provided for inspection of the cables and anchors. More recently, un-bonded tendons <br />have been used in the construction of beams, slabs, and other members; these <br />tendons are protected by grease and surrounded by plastic sheathing, instead of the <br />usual metal duct. <br />3. Category 3 Members are pre-stressed progressively as building construction proceeds and <br />the dead load increases, using bonded tendons as in Category 1. <br /> <br />4. Category 4 Like Category 3, but using un-bonded tendons as in Category 2. <br /> <br />5. Examples of construction using members of Categories 3 or 4 are relatively rare. However, <br />they will be found, for example, in the podium of a tall building or some types of bridges. <br />They require particular care in demolition. <br /> <br />18. PRETENSIONED MEMBERS <br /> <br />1. These usually do not have any end anchors, the wires being embedded or bonded within <br />the length of the member. <br /> <br />2. Simple pre-tensioned beams and slabs of spans up to about 23 feet can be demolished in a <br />manner similar to ordinary reinforced concrete, <br /> <br />3. Pre-tensioned beams and slabs will be lifted and lowered to the ground as complete units <br />after the removal of any composite concrete covering to tops and ends of the units. <br /> <br />4. To facilitate breaking up, the members will be turned on their sides. <br /> <br />5. Lifting from the structure will generally be done from points near the ends of the units or <br />from lifting point positions. <br /> <br />6. Reuse of lifting eyes, if in good condition, is recommended whenever possible. When units <br />are too large to be removed, consideration will be given to temporary supporting <br />arrangements. <br /> <br />7. Pre-cast units stressed separately from the main frames of the structure, with end anchors <br />and grouted and un-grouted ducts: <br /> <br />8. Before breaking up, units of this type will be lowered to the ground, if possible. It is <br />advisable to seek the counsel of a professional engineer before carrying out this work, <br />especially where there are un-grouted tendons, <br /> <br />9. In general, this is true because grouting is not always 100% efficient. After lowering the units <br />can be turned on their side with the ends up on blocks after any composite concrete is <br />removed. <br /> <br />17 <br />