Iran Nezam Civil Supervision Exam flashcards

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

Degree of static indeterminacy

For a plane frame it equals r + 3m - 3j, where r is reaction components, m is members, and j is joints. A positive result means redundant forces exist and compatibility equations are needed.

Point of contraflexure

The section where bending moment changes sign, so curvature reverses. In a fixed-ended beam under uniform load it lies at 0.211L from each support; in a simply supported beam under uniform load it coincides with the supports.

Euler buckling load

Critical axial load Pcr = pi^2*E*I/(K*L)^2. The effective length factor K is 1.0 for pinned-pinned, 0.5 for fixed-fixed, 0.7 for fixed-pinned, and 2.0 for fixed-free columns.

Carry-over factor

In moment distribution, the fraction of a balancing moment induced at the far end of a member. It equals 0.5 when the far end is fixed and zero when the far end is pinned.

Terzaghi bearing capacity equation

For a strip footing, ultimate capacity is c*Nc + gamma*Df*Nq + 0.5*gamma*B*N_gamma, where Nc, Nq and N_gamma depend on the soil friction angle and Df is embedment depth.

Rankine active pressure coefficient

Ka = (1 - sin phi)/(1 + sin phi), equivalently tan^2(45 - phi/2), for cohesionless backfill. The passive coefficient Kp is the reciprocal, 1/Ka, and is much larger for high friction angles.

Consolidation degree of 90 percent

Occurs when the time factor T = cv*t/H^2 reaches 0.848, with cv the coefficient of consolidation and H the drainage path length. Fifty percent consolidation corresponds to T = 0.197.

Liquefaction susceptibility indicators

Saturated loose clean sand with SPT N below about 15, shallow groundwater, and peak ground acceleration above roughly 0.15 g. Silts and uniformly graded fine sands are most vulnerable.

Pile skin friction in clay

fs = alpha*cu, where cu is undrained shear strength and alpha typically ranges 0.5 to 1.0, lower for stiff clays. Total capacity adds tip bearing q_p*A_p to the summed skin resistance.

Balanced reinforcement ratio

The steel ratio at which concrete crushing and steel yielding occur simultaneously. Sections with less steel are under-reinforced and fail ductilely, which codes require for beams.

Nominal concrete cover

Distance from the outer concrete surface to the outermost bar. It is 20 mm for mild indoor exposure, 30-40 mm for moderate, and 50 mm or more for severe or coastal exposure.

Slump test purpose

A workability measure per ASTM C143 using a standard cone. Typical values are 25-50 mm for mass concrete and 75-125 mm for normal reinforced sections; above 150 mm requires admixtures.

Fillet weld throat thickness

The effective load-carrying depth of a fillet weld, equal to 0.707 times the leg size for a 45-degree weld. Design shear strength is about 0.6 times the electrode tensile strength.

Slip-critical bolted connection

A high-strength bolted joint designed so that load is transferred by clamping friction rather than bolt shear. It requires pretension and clean faying surfaces free of paint, oil and scale.

Plastic section modulus

The modulus Z used with yield stress to obtain plastic moment capacity. The shape factor Z/S is about 1.12-1.15 for I-sections and 1.5-1.7 for solid rectangles.

Block shear failure

A connection failure combining tension rupture on one plane and shear rupture on a perpendicular plane. Capacity is approximately 0.6*Fu*Anv + Ubs*Fu*Ant, with both limits checked.

Lateral-torsional buckling limits

Unbraced beam length Lb compared with Lp and Lr sets the moment curve. Below Lp the plastic moment applies, between Lp and Lr capacity falls linearly, and beyond Lr it is elastic.

Ordinary Portland cement setting times

Initial set must occur no earlier than 45 minutes and final set within 10 hours under standard test conditions. Faster set risks placing problems; slower set delays formwork removal and finishing.

Concrete sampling frequency

At least one set of test specimens per 50 cubic metres placed, or per day of placing, whichever is more frequent. Each set normally has three specimens tested at 7 and 28 days.

Field compaction acceptance

Field dry density measured by sand replacement or nuclear gauge must reach 95-98 percent of the laboratory Proctor maximum dry density at moisture near the optimum content.

Fineness modulus of aggregate

A single number from sieve analysis describing aggregate coarseness. Well-graded sand typically has a fineness modulus between 2.3 and 3.1; gap-graded mixes need more paste and tend to bleed.

Total float formula

Total float equals late start minus early start, or late finish minus early finish. Activities with zero total float lie on the critical path, and any delay there delays project completion.

Cost performance index

CPI = EV/AC, earned value divided by actual cost. A value below 1 means the work completed has cost more than budgeted; above 1 indicates underrun relative to progress.

Excavation safety threshold

Excavations deeper than about 1.2 m require shoring, benching or safe sloping, plus inspection before each shift and after rain. Access ladders must be within a short distance of workers.

Concurrent delay treatment

When employer-risk and contractor-risk delays overlap in the same period, most contracts grant no extension of time for that overlap, though the employer may still owe prolongation cost.

Stair proportion rule

Riser height is 150-180 mm and tread 250-300 mm, with twice the riser plus the tread near 600-640 mm. Consistent riser height within a flight is required for safety.

Seismic base shear coefficient method

Base shear V = C*W, where C combines zone seismicity, soil profile, structural system, and importance factor. The equivalent static method is permitted for regular structures within height limits.

Habitable room daylight requirement

Window or glazed area of at least one-eighth to one-tenth of the floor area, with minimum ceiling height commonly 2.4-2.7 m, to satisfy lighting and ventilation regulations.

Traverse latitude and departure

Latitude equals distance times cosine of bearing; departure equals distance times sine of bearing. In a closed traverse their sums must be zero after angular and linear adjustment.

Leveling arithmetic check

Sum of backsights minus sum of foresights equals the last reduced level minus the first reduced level for a closed loop. A mismatch indicates a booking or reading error.

Horizontal curve tangent length

T = R*tan(delta/2), with R the radius and delta the deflection angle. Curve length is L = R*delta in radians, and external distance E = R*(sec(delta/2) - 1).

Rational method peak flow

Q = C*i*A/360, with Q in cubic metres per second, i rainfall intensity in mm per hour, A area in hectares, and C the runoff coefficient, for example 0.9 for roofs and 0.7 for asphalt.

Manning equation

Open channel velocity V = (1/n)*R^(2/3)*S^(1/2), where n is roughness, R hydraulic radius, and S energy slope. Roughness n is about 0.013 for concrete pipe and 0.025 for earth channels.

Stopping sight distance

SSD = V*t/3.6 + V^2/(254*(f +/- g)), with V in km/h, reaction time t near 2.5 s, longitudinal friction f near 0.35, and g the grade. It sets minimum horizontal and vertical curve radii.

Minimum storm sewer velocity

About 0.6-0.75 m/s at design flow prevents sediment deposition, while minimum pipe diameter is typically 300 mm. Maximum velocity near 3-5 m/s avoids abrasion of pipe material.

Superelevation design equation

e + f = V^2/(127*R) with V in km/h and R in metres. Maximum superelevation is commonly 6-8 percent in urban areas and up to 10 percent on rural highways.

Pavement structural number

SN = a1*D1 + a2*D2 + a3*D3, summing layer coefficients times thicknesses. The required SN from traffic load (ESAL) and subgrade support must be met or exceeded.

Asphalt compaction requirement

Field density must reach at least 92-95 percent of laboratory Marshall or gyratory density, and rolling must continue while the mat temperature remains above the cessation temperature.

Job mix formula approval

The contractor submits aggregate grading, binder content, and trial mix test results for approval before production. The supervisor verifies plant calibration and sampling at specified frequency.