Ingeniero

Preliminary design Rules of thumb

1.    The cost of reinforce concrete (in place) is usually somewhere between $100/m3 and $800/m3.  This illustrates the fact that for a "rule of thumb" to be any good, the background for its development needs to be known.  That in turn means that most of the "rules of thumb" are most applicable by the engineer that came up with them; and that everybody elsebetter be careful in using them.
2.    If placing concrete directly from a truck or concrete pump, place concrete vertically into the face of concrete already in place. Never allow the concrete to fall more than 1 to 1.5 metres. 
3.    The possible spans, and associated depths, depend on the loading to which the beam is subjected. The figures given assume 'normal' commercial building loads. Theydo not apply to more heavily loaded situations (e.g. plant rooms) or to unconventional loading scenarios.
4.    This information is given without prejudice and is for guidance purposes only.  It  is  suitable  for possibly  initial  sizing  of  structural  elements  for architectural scheme or costing purposes for  actual  building  projects  the  size  of  structural  elements  must  be veri?edthrough detailed design by a quali?ed structural engineer.
5.    Prepare drawings properly & accurately if possible label each bar and show its shape for clarity
6.     Indicate proper cover-clear cover, nominal cover or effective cover to reinforcement.
7.    Decide detailed location of opening/hole and supply adequate details for reinforcements around the openings.
8.    Use commonlyavailable size of bars and spirals. For a single structural member the number of different sizes of bars shall be kept to a minimum.
9.    Show enlarged details at corners, intersections of walls, beams and column joint and at similar situations.
10.    Congestion of bars should be avoided at points where members intersect and make certain that all rein. Can be properly placed.
11.    In the caseof bundled bars, lapped splice of bundled bars shall be made by splicing one bar at a time; such individual splices within the bundle shall be staggered.
12.    Make sure that hooked and bent up bars can be placed and have adequate concrete protection.
13.    Indicate all expansion, construction and contraction joints on plans and provide details for such joints.
14.    The location ofconstruction joints shall be at the point of minimum shear approximately at mid or near the mid points. It shall be formed vertically and not in a sloped manner.

DO NOT'S-GENERAL:
15.    Bonded reinforcement shall not extend across an expansion joint and the break between the sections shall be complete.
16.    Flexural reinforcement preferably shall not be terminated in a tension zone.
17.    Barslarger than 36mm dia. Shall not be bundled.
18.    Lap splices shall be not be used for bars larger than 36mm dia except where welded.
19.    Where dowels are provided, their diameter shall not exceed the diameter of the column bars by more than 3mm.
20.    Primary movement joints are required to prevent cracking where buildings (or parts of buildings) are large, where a building spans differentground conditions, changes height considerably or where the shape suggests a point of natural weakness. Without detailed calculation, joints should be detailed to permit 15–25 mm movement unless seismic pounding is an issue then this should be increased to min 200mm. Advice on joint spacing for different building types can be variable and conflicting. While rules of thumb are provided be sure toseek guidance of an experienced engineer. Expansion joint is a movement (functional) joint which is installed to accommodate volume change due to temperature changes, shrinkage, and change in moisture content.. The other members of this family of joints are:
o    Control (contraction) joints
o    Shrinkage strips.

According to MARK FINTEL the use of Expansion joints in a building is a...