Part I. Indicate whether true or false (T or F).

__When performing flow profile analysis, calculations always proceed in the downstream direction. That is because water flows downhill, i.e., downstream.

__Subcritical flow is controlled by upstream conditions.

__The normal depth of flow, yn, is determined by solving Manning's equation. The critical depth of flow, yc, is determined by solving the Froude number equation set equal to 1.0. Normal depth, yn, varies with flow rate, channel geometry, channel slope, and channel roughness. On the other hand, yc varies only with flow rate, slope, and channel geometry.

__Critical flow (depth) occurs at the point of minimum specific energy, where the Froude number equals 1. The depth of flow at this point is termed the critical depth and is designated as yc. At depths below yc, the flow is classified as subcritical because the depth of flow is below (sub) the critical depth, and at depths greater than yc, the flow is classified as supercritical, because the depth of flow is greater than the critical depth.

__Flows are classified as subcritical, critical, or supercritical by comparing the uniform and critical depths of flow.

__The specific energy curve is obtained by plotting specific energy for a range of depth values (y values) for a given discharge in each channel. The curve falls in the first quadrant, with asymptotes of y=E (45o line) and the abscissa (E axis). The curve has three distinct portions corresponding to subcritical, critical and supercritical flow.

__Weirs and flumes are considered critical flow measurement devices since they force the depth of flow to pass through critical depth. They are indirect measurement devices since they do not directly measure velocity or the volume rate of flow but monitor a form of energy (depth or HGL).

__Subcritical open channel flow is controlled by downstream conditions. In the case of a backwater profile (M1 or S1), the control is some type of downstream constriction (such as an undersized road cross drain) that forces the water to pond to a greater depth.

__The specific energy diagram represents a plot of the sum of the pressure head (depth of flow) and velocity head terms for a range of y-values for a given discharge.

__Given an M2 flow profile, the specific energy increases in the upstream direction (opposite the direction of flow).

__The standard step method of flow profile analysis applies only to non-prismatic channels, while the direct step method applies to prismatic channels. For the standard step method, simply stated, the solution strategy is given y, find x. For the direct step method, the solution strategy is given x, find y.

__When a storm sewer pressurizes, the HGL is indicated by the water level in a manhole, which is above the crown of the downstream pipe. When a culvert pressurizes, the headwater at the inlet is above the crown of the downstream pipe.

__A necessary condition for uniform flow is a prismatic channel, which is a channel with constant cross-sectional geometry, roughness, and slope throughout the reach of interest.

__A control is a channel feature, usually structural, that regulates the state of flow. In the pure sense, a control forces a unique relationship between depth and discharge. The most ideal control is a critical control.

__Flow profile analysis involves determination of the nonuniform flow depth along a channel.

__Culverts operate under inlet or outlet control. Under outlet control, either the condition (e.g., depth of water) at the pipe outlet or the capacity of the pipe barrel regulates the discharge through the culvert. Under inlet control, the inlet capacity, i.e., how much water the inlet can pass subject to headwater depth, regulates the discharge through the culvert. Under inlet control, the pipe barrel can carry whatever discharge passes the inlet.

__Three assumptions underlying Manning's equation are that the flow is steady, uniform, and laminar.

__In the direct step method, the only unknown, given the depths at each end of a sub-reach, is the parameter Δx.

__Steady flow is flow that does not change with time at a point (cross-section) along a channel. Uniform flow is flow that does not change in space along a channel.

__An open channel that is hydraulically mild for one flow can be hydraulically steep for a different flow rate.

__Given an S1 flow profile, the specific energy increases in the downstream direction (direction of flow).

__According to DHEC guidelines, each pump in a duplex station must be designed to pump the average daily flow (ADF).

__One day while walking along Campus Creek (Rocky Branch), President Caslen passed the Catawba Street crossing and noted the depth of flow at a point was 1.50 feet. About 20 minutes later, he reached the Sumter Street crossing and noted the depth of flow there was 1.25 feet. He concluded the flow in the reach between the two crossings was steady and non-uniform. His conclusion was correct and defensible.

__The flow along a backwater curve (M1 or S1) decelerates (slows) in the downstream direction and is subcritical for both hydraulically mild and steep sloped channels. The flow along a drawdown curve (M2 or S2) accelerates (increases velocity) in the downstream direction and is supercritical for both hydraulically mild and steep channels.

__In open channels, flow control may be generated by structures at the upstream and downstream sections (ends of channel reach under consideration), but also may be continuous along the channel. When the control results from a structure at the upstream section, we say the control is upstream, i.e., the resulting profile is controlled by upstream conditions. When the flow control results from a structure at the downstream section, we say the control is downstream. When the flow control occurs continuously along the channel, the flow is under channel, or downstream, control.

• Discuss the advantages and disadvantages of adopting a licensing system for professional engineers similar to that for medical practitioners and teachers in the UK, and as applies to engineers in other countries (e.g. USA, Canada, Australia and some European states).

Include an examination of the role of the codes and rules of conduct of engineering institutions in the UK and their effectiveness in ensuring professional standards of work.

In an industrial project, a designer wants to use W16x57, F_y = 50 ksi, of various heights, as columns.

All columns will have fixed ends at the top and bottom (K=0.5).

Note that tables for W16 are not available in the Steel Manual, as it is a special use.

Use formulas, for Euler’s buckling stress; and for short and long columns, given in the PowerPoint.

Use radius of gyration, r_y, of 1.60 inches.

Calculate the design strength, F_C P_N, (Kips) of this shape for the 15’, 30’, and 45’ column heights used in that project.

A 6-lane two-way arterial road has a maximum flow of 6,000 vehicles per hour on one
direction. It is operating at 3,600 vehicles per hour at time, t=0. A collision occurs,
blocking the two lanes, and restricting the flow of the third lane to 1,800 vehicles per
hour. After 45 minutes, the MMDA and police have cleared the incident and traffic returns
to normal as soon as the queue has already dissipated.
a. Determine the maximum length of queue that occurred.
b. How long did it take to dissipate the queue?
c. What is the average delay per vehicle?
Show all necessary solutions and diagram.

You are provided the following information about a municipal wastewater treatment plant. This plant uses the traditional activated-sludge process. Assume the microorganisms are 55 percent efficient at converting food to biomass, the organisms have a first-order death rate constant of 0.05/day, have a maximum specific growth rate of 0.1/day, and the microbes reach half of their maximum growth rate when the BOD5 concentration is 10 mg/L. There are 150,000 people in the community (their wastewater production is 225 L/day-capita, 0.1 kg BOD5/capita-day). The effluent standard is BOD5 = 20 mg/L and TSS = 20 mg/L. Suspended solids were measured as 4,300 mg-MLSS/L in a wastewater sample obtained from the biological reactor, 15,000 mg-MLSS /L in the secondary sludge, 200 mg-MLSS /L in the plant influent, and 100 mg-MLSS/L in the primary clarifier effluent. SRT is equal to 4 days.

a. (0.5 points) What is the design volume of the aeration basin (m3 )?

b. (0.25 points) What is the plant’s aeration period (days)?

c. (0.25 points) How many kg of secondary dry solids need to be processed daily from the treatment plants?

d. (0.25 points) If the sludge wastage rate (Qw) is increased in the plant, will the solids retention time go up, go down, or remain the same?

e. (0.5 points) Determine the F/M ratio in units of kg BOD5/kg MLVSS-day (assume 0.6 g MLVSS per g MLSS)?

f. (0.25 points) Determine the critical SRT value.

I. Indicate whether true or false (T for F).

__Unit hydrograph peak rate factor (PRF) parameterizes watershed runoff potential.

__The NRCS hydrologic soil group (HSG) lists soils into one of four categories (A, B, C and D) based on runoff potential. HSG-A soils typically are clayey soils with low infiltration rates and high runoff potential; HSG-D soils typically are sandy soils with high infiltration rates and low runoff potential. Information about the HSG classification for a soil is contained in the county soil survey.

__Initial abstractions, Ia, account for rainfall lost to vegetative interception, surface depression storage, and initial high rate infiltration. It is the rainfall that occurs before measurable runoff is observed.

__A unit hydrograph (UH) is defined as the runoff hydrograph resulting from 1-inch of rainfall occurring uniformly over a watershed in a specified time-period, i.e., D-hours.

__Curve number indicates the percent of rain that goes to direct storm runoff. Values are obtained from published sources as a function of land use, soil type (hydrologic soil group classification), surface cover conditions, and watershed wetness.

__Detention storage is the temporary storage of stormwater runoff; detention storage is implemented mostly to regulate the peak outflow, typically at or below a target release rate defined as the pre-development runoff peak resulting from a specified return period rainfall.

__Well-drained watersheds have high PRF values (up to 550) while poorly drained watersheds have low PRF values (as low as 180). PRF is a parameter used to compute the amplitude (peak) of a unit hydrograph. High PRF means the unit hydrograph has a higher peak, shorter recession limb, and more of the runoff volume occurring under the rising limb than does a unit hydrograph with a lower PRF value. The standard NRCS unit hydrograph has PRF=484 (English units).

__Return period is the average number of years between storms with rainfall depth equal to or greater than a specified amount. The NRCS CN runoff model is an equation to compute the runoff peak flow rate for a given rainfall.

__Direct storm runoff represents the immediate response of the watershed to a rainfall event and occurs mostly, if not entirely, as surface runoff. Flashy watersheds generally have runoff hydrographs that peak soon, have steep rising and recession limbs--all of which are indicative of an efficiently drained watershed. Flashy watersheds generally have a high percentage of clay soils and/or impervious cover, a well-developed internal drainage network, and creeks and other natural streams with small floodplains.

___ The Rational Method is a conceptual model that relates peak runoff to rainfall intensity, contributing area, and a runoff coefficient. The runoff coefficient is found in published tables and usually is expressed as a function of land use. These tables typically do not list single, unique values for the runoff coefficient. Instead, they cite a range for C-values for each land use. A general rule of thumb is to assign the higher C-values to the more frequent rainfall events and the lower C-values to the less frequent events.

___When using the Rational Method to estimate peak runoff rates, the design intensity is obtained from the appropriate intensity-duration-frequency (IDF) curve, which can be represented by either a plot of equation. The IDF curve is a functional relationship between intensity and time for a given return period.

___Two assumptions inherent in the Rational Method include are that Qp occurs when the entire watershed is contributing, and that the rainfall intensity is steady for duration equal to tc.

___The NRCS travel time method for determining watershed time of concentration provides for three distinct flow path segments. Flow path segments are sheet or overland flow, shallow concentrated flow, and channel flow. The travel time through each flow path segment is estimated by dividing segment length by velocity. The watershed time of concentration is 1.67 times the sum of the segment travel times.

___ Curve number is an index of watershed runoff potential and ranges from 0 (no runoff) to 100 (pure runoff). Practically, most watershed curve numbers occur between 60 and 90. Curve numbers are given in terms of land use, hydrologic soil group (soil type), watershed wetness, and surface cover conditions.

__Historically, time of concentration has been defined as the time it takes a drop of water to travel from the watershed boundary to the outlet. In other words, it is a measure of the time it takes the entire watershed to contribute to runoff at the outlet. For steady excess rainfall input, based on hydraulic analysis of the runoff process, time of concentration is the time it takes for the watershed to reach equilibrium, or peak runoff, conditions.

__The no-harm release rate rule for allowable (target) peak outflow rates from stormwater detention ponds states the peak must be regulated such that no offsite (downstream) flooding problems are created or aggravated. The most common release rate rule is one that states the allowable peak following land use change (post development peak) cannot exceed the runoff peak prior to land use change (predevelopment peak) for a specified design rainfall event (single objective release rate rule). An extension to this rule states the post development peak cannot exceed the predevelopment peak for the design rainfall event and more frequent events. In other words, a pond must function such that the flood (Qp) frequency curve following development is no greater than it was prior to development for all storms with return periods greater than or equal to some specified return period, typically the return period for the single objective rule.

__When using the Rational Method, the design rainfall is obtained from an IDF curve with duration equal to time of concentration. One interpretation of time of concentration, for steady rainfall, is that it is the time required for a watershed to reach equilibrium, i.e., peak, runoff conditions. Selecting a design intensity with duration equal to time of concentration assures the runoff from the contributing area above each segment in the storm sewer system will be the peak for the specified return period event.

__The primary purpose for a detention pond designed to meet the single objective release rate rule is to control the peak outflow from a site, typically following land use change that results in increased rates and volumes or runoff. To control the peak, one rule of thumb is to provide enough storage for the increase in runoff volume.

Using the column interaction diagrams in Appendix A (Concrete strength = 5 ksi, steel reinforcement yield strength= 60 ksi,) with longitudinal reinforcement ration of approximately 2%, design square columns with equal reinforcement on all sides to carry each of the following loads and select the longitudinal and transverse reinforcement: 1. Pu = 2000 kips and Mu = 160 ft.kips 2. Pu = 1000 kips and Mu = 220 ft.kips 3. Pu = 500 kips and Mu = 160 ft.kips

You are required to perform a comparative RC short column design study according to ACI 318-19 using the following information: service dead load = 800 kips, service live load = 600 kips, concrete strength = 5 ksi, steel reinforcement yield strength= 60 ksi.

1. Design a rectangular tied column the can support the given loads safely and adequately. The column width is 25 inches. Sketch reinforcement in cross-section.

2. Design a circular tied column the can support the given load safely and adequately. Sketch reinforcement in cross-section.

The rate of heat transfer, Q [energy/time = power] through a pipe wall between a fluid and the surroundings depends on fluid properties: density (ρ), viscosity (μ), specific heat (c_p [energy/temperature/mass]); and also on pipe and flow properties: the length (l), diameter (D), and thermal conductivity (λ [power/length/temperature]) of the pipe, fluid mean velocity (V), and the temperature difference (ΔT) between the pipe wall and the surroundings. Use dimensional analysis to express this system in terms of dimensionless numbers. The Π group that includes Q˙ should be expressed as a function of the other Π groups.

When confronted with a discrepancy in the plans and specifications, what form do you use to get an answer from the architect?

1- Submittal

2- AIA Form 101

3- RFI

4- RFP

Given the following excess rainfall hyetograph and 1-hr unit hydrograph, what would the 5th ordinate of the storm hydrograph be in cfs? Pn (intervals of 1 hr) = [0.2, 0.4 ,0.5 ,0.2 ,0 ,0.1] in UH (intervals of 1 hr) = [0, 100, 320, 450, 370, 250, 160, 90, 40, 0] cfs

Perform an ACI mix design using the following data (make assumptions as needed)

The 28-day compressive strength should be 4,000 psi. The concrete is to be used under exterior condition subject to deicer.

The slump should be between 3 and 4 in. and the maximum aggregate size should not exceed 1 in.

The coarse and fine aggregates in the storage bins are wet.

The properties of the materials are as follows:

Cement- Type I, specific gravity = 3.15

Coarse Aggregate:

Bulk specific gravity (SSD) = 2.70; absorption capacity = 1.1%; dry-rodded unit weight = 105 lb./ft.³

Moisture content = 2.1%

Fine Aggregate:

Bulk specific gravity (SSD) = 2.67; absorption capacity = 1.3%; fineness modulus = 2.70;

Moisture content = 2.8%