DPWH Bridge Hydraulics and Engineering Practice Flashcards

Comprehensive practice flashcards based on the FY 2027 DPWH Regional Budget Proposal lecture covering bridge hydraulics, design requirements, and engineering standards.

From a hydraulic perspective, a bridge is part of a stream crossing system that includes the approach roadway across the __________ and any openings.

floodplain

The approximate river width, $B$, is determined by the formula __________, where $c$ is a coefficient ranging from $0.5$ to $0.8$.

$$B = (c) Q^{3/4}$$

The desirable minimum bridge span length, $L$, is calculated using the formula __________, where $Q$ is discharge.

$$L = 20 + 0.005Q$$

Vertical clearance between the Design Flood Level (DFL) and the soffit of the lowest member shall not be less than __________ for rivers carrying debris.

$$1.50\,m$$

The formula used to calculate vertical clearance for navigable channels is __________, where $HV$ is the height of the vessel.

$$Vertical\,Clearance = HWL + HV + K$$

The __________ is the most commonly used equation for determining the time of concentration ($t_c$) in hydrologic analysis.

KIRPICH FORMULA

According to the Rational Formula, the discharge $Q$ is equal to __________, where $A$ is the catchment area in $km^2$.

$$\frac{CIA}{3.6}$$

The __________ equation is used to compute the Design Flood Level (DFL) by calculating velocity as $V = \frac{1}{n} R^{2/3} S^{1/2}$.

Manning’s roughness coefficient

For an Expressway, the minimum required Design Flood frequency for a river bridge is __________.

$$100\,yr$$

For a National Road, the minimum required Check Flood frequency for bridge scour is __________.

$$500\,yr$$

The __________ component of a bridge provides horizontal spans such as deck and girders and carries traffic loads directly.

superstructure

The __________ is the structure at the two ends of a bridge used for transferring loads to the foundation and providing lateral support to the embankment.

Abutment

A __________ bridge is one where the concrete deck slab works in conjunction with steel girders to support loads as a united beam.

Composite Girder

In a __________ bridge, the roadway is installed in between the top and bottom of the main girder, placing traffic completely inside the structural envelope.

Half-through

A __________ bridge is a structure where the superstructure is not perpendicular to the substructure.

skewed

Department Order No. __________ Series of 2020 prescribes guidelines on the design of bicycle facilities and the inclusion of bike lanes in bridge plans.

88

For geotechnical investigation of bridges, at least one borehole must be conducted at the proposed location of each __________ and __________.

abutment; pier

The minimum depth of a boring for a bridge foundation is __________ in ordinary soil if the foundation type is not yet identified.

$$30\,m$$

__________ scour is a lowering by erosion of the channel bed that occurs irrespective of the existence of the bridge.

General

An __________ number of spans is preferably used to avoid placing a pier at the center of a river with rapid stream flow or high debris loads.

odd

The maximum spacing for bridge drains on the deck should be __________.

$$5\,m$$

The vertical clearance above a highway roadway on a bridge shall not be less than __________, with an additional $0.15\,m$ for future resurfacing.

$$4.88\,m$$

The minimum width of a pedestrian sidewalk for a bridge in an urban area is __________.

$$1200\,mm$$

For reinforced concrete bridges, the span range for a precast slab or flat slab is typically __________ to __________.

$$6.0\,m; 12.0\,m$$

A heavy vehicle violates the law if it exceeds the permissible single axle load of __________ as stipulated in RA 8794.

$$13,500\,kg$$

The __________ analysis is used for calculating active seismic earth pressure during earthquake conditions.

Mononobe-Okabe

Level 1 Earthquake Ground Motion considers seismic hazard from small to moderate earthquakes with a service life probability of a __________ return period.

100-year

Seismic Performance Level __________ (SPL-1) ensures the bridge keeps its sound function and resists seismic forces within the elastic limit.

1

Ground Type __________ (Site Class) is characterized by a characteristic value of ground $T_G \ge 0.6\,s$ and is considered soft ground.

III

The __________ is a non-destructive method of evaluating the condition of piles by locating discontinuities such as voids or changes in cross-section.

Pile Integrity Test (P.I.T.)

The __________ or Modified Hiley's Formula is used in the DPWH specifications to compute the ultimate capacity of piles based on hammer blows.

Hiley's Formula

__________ are devices installed between the superstructure and substructure to transfer loads and provide room for rotational and translational movements.

Bridge Bearings