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
an owner wishes to form a level platform for a garden below a neighbours driveway. to do this, she intends to construct a 1.2 metre high retaining wall. as the proposed retaining wall is subject to a surcharge from the neighbours vehicle driveway, it will require a building consent. a retaining wall ranges in height from 900 mm to 1.8 metres.
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.
used for retaining wall design, 2 the live load surcharge applied on the retained soil mass behind walls to simulate the effects of vehicular traffic behind the wall, and 3 application of the new vehicle live load model and load distribution through the soil cover above culverts. the rationale for these changes and
2. how surcharge loads acts on retaining wall: surcharge loads performing on retaining wall are supplementary vertical loads that used to the backfill soil above the top of the wall. either dead loads or live loads as an instance could outcome from highway or parking lot, paving or adjacent footing.
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
retaining wall publications, software and technical guidance for the career development, information, and resources for geotechnical engineers. information includes retaining wall type, calculations, design examples, lateral earth pressures, overturning, sliding, surcharge pressure, pore water pressure, earthquake pressure, passive, at-rest, active, log spiral theory, coulomb method, graphical
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.
applying the modified boussinesq equation 1: the graph below shows the pressure distribution on an h =1m deep retaining structure caused by our notional 10kn/m line load surcharge q as we vary the distance of the surcharge from the back of the wall m .
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
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
it should cover most vehicle loads provided they are not immediately up against the back face of the wall. check aashto for different amounts of surcharge for different height walls. the surcharge can be 2 feet or more of earth surcharge, but 250 pdf minimum.
foundation walls and other walls in which horizontal movement is restricted at the top shall be designed for at-rest pressure. retaining walls free to move and rotate at the top shall be permitted to be designed for active pressure. design lateral pressure from surcharge loads shall be added to the lateral earth pressure load.
sloping ground in front of wall and flat ground behind wall with building or vehicle surcharge 1/ reduced soil at base of wall to resist sliding 2/ increased loads on wall. 3/ stronger wall required than profile 2. 4/ foundation and toe depth needs to be increased over profile 2 wall.
simplified methods for the surcharge lateral pressure distribution kumars zand-parsa department of civil engineering, azad university and caltrop consultant eng. co. 1516 w 1 st st. 315 san pedro ca 90732 abstract a surcharge load is any load such as spoil embankments, street s or highways, construction machinery which is imposed upon the
the general guideline below is specific to embedded retaining wall. see ciria 580 and euro code 7 for detailed advice. the euro code 7 approach differs from the gross pressure cp2 and net total pressure methods burland and potts which apply a fos to the respective gross and net resistings moment against overturning moments in applying factors to the mobilised values of ø¹ and c¹ whilst
distributed surcharge \i tl 1111 ml i retaining wall pressure due to equivalent surcharge pressure due to backfill only figure 1. traditional method of estimating lateral pressure due to surcharge load. ies in which the magnitude and distribution of lateral pressures on a retaining 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
as is often true for any structure, the most dangerous time for the structure is during construction. this is especially true for retaining walls and similar structures. during construction, heavy equipment may be operating close to the wall imposing large 'surcharge' loads, impact loads and similar forces on only partly consolidated backfill.
glance over table 3-1 design lateral soil loads on page 7 and be familiar with that table and the footnotes given there. under aashto most retaining walls that are subject to vehicle loads require some amount of additional backfill to be included to simulate a vehicle surcharge load.
all other retaining wall conditions such as taller walls, tiered walls, and/or walls supporting sloping backfill or other surcharges will generally require a building permit. when a building permit is required a building permit can usually be issued over the counter when two copies of the following are
models have been developed to represent the horizontal load surcharges on abutment walls, wing walls and other earth retaining structures due to traffic loads. these models have been
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. axial load applied to top of stem
2. surcharge loads: the term surcharge refers to an additional loading on the proposed wall system. this term usually refers to traffic loading that is in proximity to the wall system. use the spangler method of analysis area load of finite length or boussinesq method of analysis
h 300 design loads and distribution of loads h 310 general requirements all structures should be designed to sustain, within the allowable stresses, all applicable design loads and forces which are properly distributed. allowable stresses are discussed in subsequent chapters, according to the type of material. standards to be used in the
surcharge loads acting on retaining wall. surcharge loads acting on retaining wall are additional vertical loads that used to the backfill soil above the top of the wall. it can be either dead loads for example sloping backfill above the wall height or live load which could result from highway or parking lot, paving or adjacent footing.