Structural Collapse Technician Training FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Structural Collapse Technician Training Module : 4 - Part b Lifting & Moving Airbags Lifting Considerations & Stabilization Calculating Weights No Changes in 2012 Jan08 27Jan09 Jan09

High Pressure Air Bags Characteristics Neoprene/butyl rubber FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags Characteristics Neoprene/butyl rubber Steel kevlar reinforced Variety of sizes Maximum capacity is calculated at 1 inch of lift Capacity reduced at max height Construction of the bag and rated capacities of air bags will vary, depending on age and manufacture. Today’s high pressure bags are commonly rubber coated, Kevlar reinforced. NOTE: the rated capacity identified by the manufacture is calculated at maximum 1 inch lift. This is based on surface contact with the material being lifted and the surface of the air bag. The higher the lift, the capacity is reduced. Jan09

High Pressure Air Bags Application Maximum stack of two high FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags Application Maximum stack of two high Lift is limited to capacity of small bag Larger bag on bottom Centers of bags MUST be aligned There are many instructional techniques to using air bags. The following are offered as general guidelines, however, one should always use the guidelines as provided by the manufacture. Stacking air gas - maximum two high Lifting capacity limited the the capacity of the smaller bag Place larger bag on the bottom Align bags for lift stability Jan09

Animated Slide (10 seconds) FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Airbag Lift Give this slide some time to load, it is automated. It is a good demonstration Animated Slide (10 seconds) Jan09

LOAD High Pressure Air Bags BASE OF SUPPORT FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags COLUMN OF AIR LOAD BASE OF SUPPORT Increased surface area = Increased lifting capacity Airbag lifts are based on the principle of surface area to object lift ratio. An airbag is rated for lift at maximum surface area contact. When the surface area in contact with the object decreases the lifting capacity of the bag decreases proportionally. Jan09

LOAD High Pressure Air Bags AIR BAG INFLATED FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags AIR BAG INFLATED REDUCED SURFACE AREA CONTACT LOAD OFAIR COLUMN The lifting capacity of an airbag can be determined by multiplying the surface area in contact with the object by the operating pressure used to fill the bag with air. The important concept to reinforce is that if you lack the surface area to lift the object, the capacity of the bag is immaterial. BASE OF SUPPORT Jan09

High Pressure Air Bags Weight Dimension Capacity Lift Ht. 6”x 6” FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags Weight Dimension Capacity Lift Ht. 6”x 6” 1.5 Tons 3” 2 lbs 6”x 12” 3.2 3.5 3 10”x 10” 4.8 5 4 15”x 15” 12.0 8 10 15”x 21” 17.0 9 13 20”x 20” 21.8 11 16 24”x 24” 31.8 22 28”x 28” 43.8 30 36”x 36” 73.4 20 48 Table of most available sizes. Capacities are for Kevlar, high pressure bags Effective area in contact is between 72% and 96% of the calculated area using the dimensions of the bag. Jan09

High Pressure Air Bags Manufacture’s I.D. Tag FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags Manufacture’s I.D. Tag Manufactures I.D tag indicates: *Lifting capacity *Lifting height *Maximum working pressure *Maximum air capacity Note that this is15” x 15” Bag. If you calculate 15 x 15 x 118 psi, you get 26,550 lbs or 13.3 tons The Rated Bag Capacity is12 tons, therefore 90% of area is in contact. Jan09

High Pressure Air Bags & Cribbing FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes High Pressure Air Bags & Cribbing The instructor should reinforce the concept of lift and inch and crib and inch. In addition, the lifting and cribbing point must be in separate locations on the object being lifted. Never place hands or any other art of the body under any portion of the object being lifted. In addition, as the airbag inflates and the surface area in contact decreases, the bag becomes more unstable. The rescuer should be cautious that the bag does not kick out during the lift. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Spreading & Pushing Air bags can also be used to spread and object as is illustrated in this photo. Movement on the objects will be effected by weight, surface contact and friction. As a general rule of thumb, the “lighter’ object will move. Jan09

Lifting & Stabilizing Irregular Objects FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Lifting & Stabilizing Irregular Objects Irregular objects have surface area contact and center of gravity considerations that are entirely different than geometrically shaped objects. Special emphasis should be placed on using stable lifting points and proper cribbing techniques with irregular shaped objects. As with all lifts, plan your lift and anticipate movement Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Pipes & Cylinders Round or cylindrical shaped objects require two lifting points. Inflating both bags at the same time may be effective, this must be done with clear communication, cribbing and safety in mind. Round objects will roll if not properly controlled Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Inflating Air Bags There are many pre-manufactured air supply “Cart” available for rescue team use. These systems may be used to supply breathing air or provide power to work pneumatic tools, like air bags. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Slow and deliberate lifting requires constant stabilization along the way. These two teams are trying to see who can safely pop their balloon first. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes There are many ways to lift a heavy pipe. All of them involve relatively unstable shoring techniques. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes OOPS! These timbers should have been placed sideways making the lifting surface wider than it is taller. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Lifting in conjunction with moving requires braking systems, hauling systems, and lifting systems all working in harmony. Jan09

Lifting Considerations FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Lifting Considerations Jan09

Lifting Or Moving A Load Functions to be addressed FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Lifting Or Moving A Load Functions to be addressed Center of Gravity Load Stability Wedges & cribbing Estimating Load Weight Lifting Functions Critical angle These are important considerations to be addressed before any load is lifted or moved. If any of these functions are not addressed or miscalculated the lift may not be successful.. Jan09

Center of Gravity & Load Stability FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Center of Gravity & Load Stability Stable Unstable CG The left illustration depicts an object that is rigged over it’s center of gravity (CG) and is stable. If it is not it will swing into a position that has the CG under the hook. This has potential of injuring rescuers and/or victims The right illustration shows and object that is rigged below it’s center of gravity (CG). In the case of the second illustration, the object would be very unstable when lifted. This is most common when lifting long slender objects. This problem can be eliminated by either attaching the rigging above the CG or laying the object flat and using 2 points of attachment CG Connection point below CG makes object unstable. Jan09

Wedges, Shims & Cribbing FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Wedges, Shims & Cribbing Yes! there is a technical difference, wedges are used to change direction and shims take up space. For the purpose of this class, the terms “wedges” and/or “shims” will be considered the same. Ask for what you what: 2 – 4” x 4” wedges or 2 – 2” x 4” wedges, Wedges can be used to change the angle of the box crib to match the surface angle of the object being lifted. Wedges are used to take up the void space when there is not enough room for a full piece of cribbing. Jan09

Wedges Wedge (mechanics) FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Wedges Wedge (mechanics) Technically is a portable double inclined plane, a wedge is a simple machine used to separate two objects, or portions of objects, through the application of force, perpendicular to the inclined surfaces, developed by conversion of force applied to the blunt end. The mechanical advantage of a wedge depends on the ratio of its length to its thickness. Jan09

Use of wedges to change direction FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Wedges Single wedges are used to change the angle of a box crib to match the surface of the object or material being lifted. In addition, wedges can take up the void spaces. Actually in this configuration they should be called Shims Use of wedges to change direction Jan09

What if one wedge is Upside Down? FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes “Marrying” Wedges (repeated from 2b) Sloped Surfaces Must Be in Full Contact 1” min. Full Driven Over Driven Under Driven Best O.K. Wrong Bad Marriage, means Bad Bearing. The main issue is that all wedge sets need to be fully driven or slightly over driven. Inclined planes of both wedges must be touching each other. Re: use of wedges with one turned over. It can happen, and it probably would be OK especially in 2x4 wedges with gussets each side, however this should be discouraged. It is inconsistent with accepted training. If one is turned over, the cut surface will not be in full contact w/ the smooth surface, so friction & contact will be less. Also the end will not be vertical for driving What if one wedge is Upside Down? This is NOT RECOMMENDED. It is better to have the cut surfaces together – more friction & better fit Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes 2x4 Wedges 2x4 wedges are often needed for smaller adjustments than are possible with 4x4 wedges. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Shims Shims are used to fill space, opposed to wedges that lift, load or charge objects. Jan09

Shims Note that there are two shims in this photo. FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Shims Note that there are two shims in this photo. Jan09

Box Cribbing 6000 lbs. per contact point FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing 6000 lbs. per contact point Four point system Nine point system Illustration of box cribbing. The capacity of cribbing system is determined by the number of contact points, described as surface area and then multiplied by 500 lbs. Example: 4” x 4” four point system - 500 x 3.5 x 3.5 = 6,125 rounded off to 6,000 lbs per contact point. The 500 psi is the approximate strength of the contact points for Douglas Fir. And Southern Pine For softer wood species, such as pine & spruce, the strength would be reduced to about 75% for Eastern Softwoods & Western Cedar and 85% for Spruce-Pine - Fir and Hem-Fir. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing TIER 3 X Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing 3x 2x 4x Solid Jan09

Box Cribbing 6000 lbs. per contact point FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing 6000 lbs. per contact point Jan09

Box Cribbing Object Must have full bearing with crib Contact Points FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing Object Must have full bearing with crib Contact Points Jan09

Box Cribbing Least desirable layout FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing Least desirable layout Each crib is only supporting 6000 lbs Not very stable Height to width 1 to 1 Jan09

Can be as little as 1 to 1 with angle situations FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Box Cribbing Can be as little as 1 to 1 with angle situations Jan09

Crib Stability Load should be centered! FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Crib Stability The box crib system should be built to allow the load to run center of the box crib. This will create the most stability per available surface area, and the highest strength, since all the bearings will be loaded the same. Load should be centered! Jan09

Crib Stability LOAD CENTER MUST 1/3 of BE CRIB FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Crib Stability LOAD MUST BE CENTER 1/3 of CRIB If the center of the load is kept within the center 1/3 of the of the crib, all bearings will be in compression. Things will be relatively stable However, as the center of load nears the 1/3 point, the bearings nearest the load center will have higher stress than those farther away. Also, the crib will not be able to support as much, since the higher stressed bearings will start to compress, and de-stabilize the system Jan09

Crib Stability Load is not within mid-third at bottom FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Crib Stability Load is not within mid-third at bottom LOAD MUST BE CENTER 1/3 of CRIB This would be an undesirable system and very unstable Jan09

Change Angle Use of wedges & shims FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Change Angle Use of wedges & shims Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Martian Cribbing Martian cribbing. Just adding a little levity to the training. Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Cribbing This is an example of cribbing and supporting a large object. See how many in the class observe less than ideal conditions. How would they correct the condition? Jan09

FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Calculating Weights Jan09

Weights of Building Materials WIDTH x HEIGHT x LENGTH = CUBIC FT FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Weights of Building Materials WIDTH x HEIGHT x LENGTH = CUBIC FT Reinforced concrete = 150 pcf Concrete columns & beams weigh more (16”sq w/ 5% rebar = 170pcf) Steel = 490 pcf Use Area Method – later slides Earth = 100 to 125 pcf Wood = 35 pcf (dry) – use 40 Note that heavily reinforced concrete beams and columns could weigh as much as 200pcf Next 3 slides show methods for calculating the weights of simple concrete shapes. Weights of other materials may be found in the same way There are quicker ways of calculating weights of concrete slabs and walls, that are given in Module 2a. One just needs to remember that a 12: concrete slab weighs 150psf Then 10” = 125psf, 8” = 100psf, 6” = 75psf and so on This is called the area method and it will be presented as a quick way to estimate the weight of steel, following the 3 concrete weight slides Jan09

Calculating Weight Concrete Rectangle FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Calculating Weight Concrete Rectangle WIDTH x HEIGHT x LENGTH x WEIGHT 4’ x 2 ’x 20’ = 160cf x 150pcf = 24,000 lbs. 4 feet 2 feet Example of figuring the weight of a rectangular section of concrete. Or quick way 2’ slab = 300psf Total weight = 300 x 4 x 20 = 24,000lb 20 feet Jan09

Calculating Weights Concrete Round FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Calculating Weights Concrete Round 0.8 DIAMETER2 x LENGTH x WEIGHT 0.8 x 3’ x 3’ x 20’ = 144cf x 150pcf = 21,600 lbs. 3 feet Example of figuring the weight of a section of round concrete column. 20 feet Jan09

Calculating Weight Concrete Pipe FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Calculating Weight Concrete Pipe Weight of Solid Round – Weight of Hole 0.8 (4’x 4’- 3’x 3’) x 20’x 150pcf 112 cu-ft x 150pcf = 16,800 lbs. 4 feet diameter Example of figuring the weight of a section of concrete pipe. This is a more exact method than was shown on previous version of this document The other way of finding this weight is to measure all around the pipe (which is a little over 3 times the diameter). Then use that measurement as the width of a flattened slab. In this case that would give one 75psf (for 6” thick) x 3x4 (distance around pipe) x 20ft = 18,000lb this is a little high since the pipe is fairly thick. The answer more accurate for thin steel pipes 6” thick 20 feet Jan09

Estimating Steel Weight - Area Method FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Estimating Steel Weight - Area Method 12” 12” Steel weighs 490 lbs per cubic ft Steel 1” thick weighs 490pcf / 12” = 40.8 psf For steel weight per square foot use: 1” thick Use 40 lbs ¾” Use 30 lbs ½” Use 20 lbs ¼” Use 10 lbs 12” 12” 1” 12” This is a method for calculating the weight of steel sections All one needs to remember is that one square foot of steel plate weighs about 40 lbs. The slide gives weights for ¾, ½ & ¼” Ask students for weight of 1/8”, 3/8”, 5/8”, 1 ¼” etc Jan09

Area Method Example - 1 Pl 36" x 2" Pl 12" x 2" ea end Pl 36" x 2" FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Area Method Example - 1 What is weight of this 36ft long steel section? 2” Steel = 2 x 40 psf = 80 psf Area per ft = 2 x 3 sq ft + 2 x 1 sq ft = 8 sq ft Weight per ft = 8 x 80 = 640 plf Total weight = 640 x 36 = 23,040 lbs Exact weight = 652.8 plf (only 2% off) Make sure all understand this example This same example was used in SCT02a Pl 36" x 2" Pl 12" x 2" ea end Pl 36" x 2" Jan09

Area Method Example - 2 Pl 24" x 5" Pl 12" x 3.5” Pl 24" x 5" FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Area Method Example - 2 What is weight of this 20ft long steel section? 2 Flanges 40 psf x 5” x 2 ft x 2 = 800 plf Web 40psf x 3.5” = 140 Weight per ft = 800 + 140 = 940 plf Total weight = 940 x 20 = 18,800 lbs Exact weight = 958.8 plf (only 2% off) Again, take the time to assure everyone understands Pl 24" x 5" Pl 12" x 3.5” Pl 24" x 5" Jan09

Calculate Steel Weight FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Calculate Steel Weight Jan09

Review & conclusion of Part b FEMA US&R Response System Structural Collapse Technician Training Module 1 c Structural Eng Sys Part 5- Instructors Slides + Notes Review & conclusion of Part b Review Airbags Lifting Considerations & Stabilization Calculating Weights Questions? Discussion? Next: Part c Cranes, Rigging & Bolting Jan09