calculation of factors of safety against overturning and sliding for a cantilever retaining wall with uniform surcharge loading www.engineeringexampl
live load surcharge is considered when vehicular actions act on the surface of backfill soil at a distance which equal or less than the wall height from the wall back face. active pressure from uniform surcharge is explained in the figure 2.
machinery on non structural slab adjacent to or on wall will increase soil lateral pressure to wall but less then machinery directly on soil due to slabs pressure dissipating effect. instead of 170 ib/ft2 two feet heavy soils efp , we use 45 efp as surcharge from machinery on non structural stab on 8 feet backfill. non
examples of live load surcharges are vehicular traffic and bulk material storage facilities. dead load surcharges, on the other hand, are considered to contribute to both destabilizing and stabilizing forces since they are usually of constant magnitude and are present for the life of the structure. the weight of a building or another retaining wall above and set back from the top of the wall are examples of dead load surcharges.
751.24 lfd retaining walls. retaining wall shall be designed to withstand lateral earth and water pressures, including any live and dead load surcharge, the self weight of the wall, temperature and shrinkage effect, live load and collision forces, and earthquake loads in accordance with the general principles of aashto section 5 and the general principles specified in this article.
point load surcharges applied at a setback distance greater than 1h july 1, 2014 website admin uncategorized a 15 ft retaining wall with a 16 thick footing h=16.33 has a point load surcharge of 4 kips at 21 ft setback x=21 .
surcharge load on plan ; surcharge = 60.0 kn/m 2 applied vertical dead load on wall ; wdead = 40.0 kn/m applied vertical live load on wall ; wlive = 5.0 kn/m position of applied vertical load on wall ; lload = 0 mm applied horizontal dead load on wall ; fdead = 0.0 kn/m applied horizontal live load on wall ; flive = 0.0 kn/m
sketches of the retaining wall forces should be considered to properly distinguish the different forces acting on our retaining wall as tackled in the previous article, retaining wall: a design approach. based on our example in figure a.1, we have the forces due to soil pressure, due to water and surcharge load to consider.
typical live load surcharges are 100 psf for light traffic and parking, and 250 psf for highway traffic. both the toe surcharge and the heel surcharge have associated checkboxes that can be used to dictate whether the respective surcharges should be considered as resisting sliding and overturning of the wall.
wall backface to vertical surcharge r = ft. live load surcharge height hsur = ft. aashto table -2 vehicle collision load tl-4 pct = kip aashto table a13.2-1 collision load distribution lt = ft. aashto table a13.2-1 top of wall to point of collision impact on rail hct = ft. 1. stability checks 1. eccentricity 2. sliding 3. bearing applied loads
surcharge location is 0 feet from shoring/retaining wall height of retaining wall/shoring is 10 feet traffic surcharge = × = 30 pcf given in this example x 3.5 ft from table 1 = 105 psf. this surcharge shall apply as a rectangular distribution to the full height of shoring. ii.
vertical line load behind wall l - lb/ft or n/m height of retaining wall h - ft or m horizontal distance from wall to line load d - ft or m output: login to enable the formulas not a member? join now height to resultant, hr = line load surcharge resultant, rl = overturning moment from point load, ml =
equivalent surcharge and shows a 2 foot scaled; not specified fill on top of a retaining wall backfill. elsewhere .. question where was the 250 psf uniform surcharge originated from? question practically, in reality, there is no such a uniform, infinite long strip load of 250 psf. 6 common cases conventional construction equipment
in this example, the surcharge from a 10kn/m line load located just outside the area of influence could contribute and extra 113% to the load on the shoring frame. in this example, even thought the surcharge load is the same, relative to the size of the earth pressures, it seems much less significant.
the surcharge will be a point load of 106 kips adjacent to the retaining wall. the smallest dimension of the wheel contact area is 13.4'. using that dimension as the design strip width will result in a surcharge lateral pressure of 8.5 klf/ft on the retaining wall assuming ka = 0.5 .
re: traffic live load surcharges on retaining walls fndn geotechnical 4 nov 05 15:01 sometimes the 250 psf vertical stress is converted to 80 psf equivalent fluid pressure and may be added to the equivalent active soil backfill pressure of 35 to 50 psf.
helpful retaining wall problem with a surcharge load. great geotech type problem for the pe exam head to www.civilengineeringacademy.com for more including a great practice exam. here's the link
in the conventional design of retaining walls and bridge abutments, the lateral earth pressure due to live load surcharge is estimated by replacing the actual highway loads with a 600 mm layer of
the basic pressure loading to be considered for the design is: normal loading = static earth pressure water pressure pressure due to live loads or surcharge. in general, the resulting design pressure for earth retaining structures should not be less than the pressure due to a fluid of unit weight 5kn/m 3.
a surcharge load results from forces that are applied along the surface of the backfill behind the wall. these forces apply additional lateral forces along the back of the wall. this spreadsheet calculates the resulting pressure field acting on the retaining wall due to a point load at a given position behind the wall.
in the conventional design of retaining walls and bridge abutments, the lateral earth pressure due to live load surcharge is estimated by replacing the actual highway loads with a 600 mm layer of backfill. this original recommendation was made several decades ago when the highway truck loads were much lighter.
where a semi-gravity wall is shown, the live load surcharge is placed over any element of the ers for settlement and bearing analysis, while the live load surcharge is placed behind all the elements of the ers for sliding, and eccentricity analysis. note that the live
the live load surcharge is found by taking the axle load and distributing it over an area equal to axle spacing multiplied by the track spacing, generally 70 square feet.
lateral forces on retaining wallsence 454 assakkaf design of retaining walls the design of retaining wall must account for all applied loads. the load that presents the greatest problem and its primary concern is the lateral earth pressure induced by the retained soil. the comprehensive earth pressure theories
timber. each of these walls must be designed to resist the external forces applied to the wall from earth pressure, surcharge load, water, earthquake etc. prior to completing any retaining wall design, it is first necessary to calculate the forces acting on the wall. retaining wall to support a fill. retaining wall to support a cut. cut fill