civil engineering

  From section B-B, Let us consider a box culvert of size 4x4 m. A = clear span. Clear span is the discharge volume.  Clear span width is based on inflow and outflow of water. Based on factor of safety and H.F.L clear span volume will be decided. In factor of safety for load calculation we have to consider 2.5 times ( according to code book ) more than actual load.  F = wall thickness, B = height of vent.  The above figure is the single vent.  If there is heavy flow, then provide another vent beside the existing vent.  Here you can increase the size of vent when it is heavy flow, but because of heavy flow there will be damage in the outside discharge d/s side. The damage occurs because heavy flow occuring in the same place continuously.  Due to this reason, when there is heavy discharge another vent will be provided beside the existing vent. In previous days culvert size will be taken as 2.5 m. After letter issued by forest department then size of culvert is minimum 4 m clear span and

  Culvert: culvert means a types of structure which allows water to flow under a rail road, road or any obstruction from one side to other side. Types of culverts: slab culvert box culvert single pipe culvert multiple pipe culvert single arch culvert multiple arch culvert Box culvert: It is a short span bridge , over highways, water ways, railways etc.  Steps for construction of box culvert: Layout and excavation:  Layout of any structure shows the plan of its foundation on ground surface according to its drawings. After this excavation work will be carried out exactly.       2. Compacting the soil:            Soil compaction must be done to reduce the void space between soil particles.              3. Laying of profile correction course (PCC):        4. Placing of reinforcement for raft (foundation):             5. Shuttering for raft foundation             6. Casting of raft             7. Shuttering for bottom haunch:              8. casting of bottom haunch              9. Fixing o

A mat foundation is also called as raft foundation. A raft foundation is a thick reinforced concrete slab which supports all the load-bearing walls and column loads of a structure or a large portion of structure. Principles and design of mat / raft foundation: When the loads are heavy and the soil is very weak or highly compressible in this condition mat foundation is required. A raft foundation is more economical than individual footings when the total base area required for the individual footings exceeds about one-half of the area covered by the surface. For individual footings when the soil mass has very erratic properties and contains lenses of compressible soil in this case a raft foundation is preferred. If individual footings are provided in such a case, it would be difficult to control the differential settlements. Raft foundations are generally at some depth below the ground surface, a large volume of soil is excavated and the net pressure on the soil is considerably reduced