Egypt Engineering Consultant Civil flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Degree of static indeterminacy

Number of unknown reactions plus internal forces minus available equilibrium equations. In 2D, three equations exist per free body, so a propped cantilever is one degree indeterminate.

Euler buckling load

Critical axial load for a slender column given by Pcr = pi squared times EI divided by effective length squared. Effective length factor depends on end restraint conditions.

Terzaghi bearing capacity equation

Ultimate bearing pressure for a strip footing equals cohesion times Nc plus surcharge times Nq plus half gamma B N gamma. Bearing capacity factors depend on friction angle.

Consolidation settlement formula

Primary settlement equals Cc times thickness divided by one plus initial void ratio, multiplied by log of final over effective initial vertical stress ratio.

Balanced reinforcement ratio

Reinforcement ratio at which concrete crushing and steel yielding occur simultaneously. Computed from concrete strength, steel yield strength, and steel elastic modulus.

Lateral-torsional buckling

Failure mode of steel beams bent about the strong axis when unbraced length exceeds a limit. Nominal moment reduces below plastic moment capacity as unbraced length grows.

Total float in CPM

Difference between late start and early start, or late finish and early finish. Activities with zero total float form the critical path controlling project duration.

Earned value cost performance index

Ratio of earned value to actual cost. Values above one indicate under-budget performance; values below one indicate cost overrun on the project.

Manning equation

Empirical open channel velocity formula: velocity equals one over roughness coefficient, times hydraulic radius to two-thirds power, times slope to one-half power.

Rational method peak flow

Peak discharge equals runoff coefficient times rainfall intensity times catchment area, with a unit conversion factor. Assumes uniform rainfall over the catchment.

Stopping sight distance

Distance for a driver to perceive, react, and stop before an obstacle. Sum of reaction distance and braking distance, adjusted for roadway grade.

Superelevation minimum radius

Minimum horizontal curve radius equals design speed squared divided by 127 times the sum of superelevation rate and side friction factor.

BOD exertion equation

Biochemical oxygen demand at time t equals ultimate BOD times one minus exponential of negative rate constant times time. Standard test measures five-day demand.

Sedimentation overflow rate

Flow divided by surface area of settling basin. Particles with settling velocity greater than or equal to this rate are completely removed in ideal conditions.

Bowditch traverse adjustment

Method distributing closure error in proportion to leg length. Corrections applied to latitudes and departures so the traverse closes exactly.

Azimuth from coordinates

Horizontal angle measured clockwise from north, computed as arctangent of easting difference over northing difference. Quadrant must be resolved correctly.

Engineer sealing work

A licensed engineer may seal only drawings and calculations personally prepared or directly supervised. Sealing unreviewed work of others is unethical.

Egyptian concrete cover

Minimum distance from bar surface to concrete surface, specified by exposure condition. Typically 25 mm slabs and 40 mm beams in mild exposure.

Characteristic concrete strength

Compressive strength below which no more than five percent of test results are expected to fall. Determined from standard cube or cylinder tests at 28 days.

Concrete slump test

Workability measure recording vertical settlement of a concrete cone after removal. Typical values range from 25 to 100 millimetres for normal construction.

Net present value

Sum of discounted cash inflows minus outflows over project life. Positive value at the required rate of return indicates an economically acceptable project.

Benefit-cost ratio

Present worth of benefits divided by present worth of costs. A ratio greater than or equal to one indicates the project is economically justified.

Seismic base shear

Total lateral design force equal to seismic response coefficient times seismic weight. Coefficient depends on spectral acceleration, response modification, and importance.

Ductile detailing

Detailing provisions ensuring structures deform without brittle failure. Includes closely spaced confinement, strong-column weak-beam hierarchy, and adequate joint shear capacity.

Time of concentration

Time for runoff to travel from the most hydraulically remote point to the outlet. Used as storm duration in the rational method.

Curve number method

Estimates direct runoff from rainfall using soil group and land cover. Potential retention relates to curve number; runoff computed from rainfall excess.

Retaining wall sliding factor

Ratio of resisting horizontal forces to driving horizontal forces. Minimum acceptable value typically one and a half for stability against sliding.

Wellpoint dewatering

System of shallow wells connected to a header pipe and pump. Effective for lowering groundwater up to about five metres in permeable soils.

Prestress losses

Reduction in initial prestress from elastic shortening, creep, shrinkage, relaxation, and friction. Typically fifteen to twenty-five percent for post-tensioned members.

Bridge scour

Erosion of bed material around piers and abutments from flowing water. Estimated by empirical equations considering flow depth, velocity, and pier geometry.

Coagulation optimum pH

pH range where coagulant achieves best particle destabilisation. For alum, optimum typically lies between six point five and seven point five.

Water hammer pressure surge

Pressure rise from sudden velocity change in a pipe, equal to density times wave speed times velocity change. Mitigated by surge tanks and slow valve closure.