TILT-UP CONSTRUCTION - Brock White

Panel ErectionInformationPanel ErectionInformationRigging and the CraneGeneralThe most important phase during the construction of a tilt-upbuilding is the erection of the wall panels. It is extremelyimportant for the designers and contractors to plan and replanthis portion of the job. They should direct their efforts toensure that this important phase of construction is performedsafely and efficiently.Prior to ConstructionPrior to the actual start of construction, an inspection of thesite should be made by the contractor. The location of thejobsite may be such that special permits will be requiredto gain access to the site for heavy equipment such as thecrane. As an example, permits are a common requirementfor schools and church projects. These projects are usuallybuilt in residential areas where weight and size restrictionsmay exist.It is advisable for the contractor to investigate restrictions onearly daily start-up times. Many areas have noise abatementand dust control regulations. Also, the panel contractor anderection contractor should walk the site and determine a suitablelocation for the crane assembly and rigging make-up.Some local governments will not allow this activity on publicstreets.It is also advisable that any problems with uneven terrain benoted at this time and dealt with prior to bringing the craneonto the jobsite.The panel contractor and the erection contractor shouldalways agree on a location for both the crane entrance ontothe floor slab as well as the exit ramp off the floor slab. Ifnecessary, plans should be made to thicken the floor slabat these ramp locations so the crane weight will not damagethe edge of the slab.Since there must be a close, cooperative relationship betweenthe panel contractor and the erection subcontractor, itis advisable to select an erection sub-contractor during theearly days of the project. The erection sub-contractor andcrew should be well experienced in tilt-up, as panel tiltingand handling is a very specialized skill.sary to shut off the power in some overhead wires in orderto safely operate the crane during panel erection. Mostsafety regulations dictate that cranes will not be allowed towork closer than ten feet to power lines.The quality of the floor slab on a tilt-up project cannot beover emphasized due to the heavy weights that the slab willbe expected to support early in its life. Equally as importantas the slab, is the sub-base under the floor slab. When itcomes to supporting the combined weight of the crane andtilted panel, the floor slab is no better than its sub-base.Even a thick, properly engineered floor slab with two curtainsof reinforcing steel will not support the weight of the crane ifthe sub-base is unstable.To insure an efficient construction procedure, careful considerationmust be given to the casting location of the panels.The following two important criteria must be met if the contractorexpects to have a successful project:• Panels must be located for efficient CASTING.• Panels must be located for efficient LIFTING.The panel contractor should work with the erection subcontractorin developing the panel casting layout. The erector’sadvice should be sought so that the panels are cast in sucha position that a properly sized crane can safely reach anderect them.Underground tunnels, trenches and sewer lines are a verycommon occurrence and can create problems. It is necessaryto know the location of these underground hazardsand to avoid those that may need strengthening in order tosupport the crane’s weight. We have often found that thelocation of these underground hazards is not always notedon the architect/engineer’s plans. Further investigation bythe panel contractor should be made in an effort to discoverthese types of unknown hazards.Overhead electric or telephone wires can be a commonproblem on both urban and rural job sites. It may be neces-Crane CertificationThe crane that is finally selected for the project should beproperly certified. Many, if not all states have standardswith which erection sub-contractors must comply. Prudentcontractors make certain they have available at the jobsitePrior to ErectionSite InspectionAfter the panels are cast and curing, the panel contractor,erection sub-contractor, and the accessory supplier shouldagain walk the site. The terrain upon which the crane willtravel should be inspected and any further corrections noted.Crane selection should not be looked on as merely routine.General rules for sizing the crane state that the cranecapacity should be a minimum of two to three times that ofthe heaviest panel including the weight of the rigging gear.However, in the final analysis not only the panel weight, butalso the crane’s position relative to the panel must be considered:The following questions must be answered before finaldetermination of crane size can be established:• How far must the crane reach to lift the panel?• How far will the crane have to travel with the panel?• How far will the crane have to reach to set the panel?documentation attesting to the crane’s certification. The contractorshould also obtain a certificate of liability insurancefrom the erection sub-contractor.Corrective actions shall be taken prior to erection of thepanels.Entrance and exit ramps should be checked. The entranceramp should be built up so the crane descends slightly down20 02-09