Technical memorandum -Senior Capstone Project

MEMORANDUM

Team: Lancer Parking Solutions/ California Baptist University (CBU)

To: Dr. Frederick Pontius/ CBU College of Engineering

From: Manzi Roger Dusabimana

Date: March, 3rd, 2014

I. Introduction

In the past few years California Baptist University (CBU) has been growing at a

remarkably high rate. This growth is due to the high enrollment rate which goes hands in hands

with the number of the university’s staff and visitors. Having been trained to identify a problem

in the society and use our engineering training to develop solutions, Lancer Parking Solutions

has proposed the construction of a multi-story parking garage, a structure that would enormously

help accommodate the growth of the campus.

From September to December 2013, Team Lancer Parking Solutions has held several

meetings with the client (CBU) during which the site location was chosen, the design capacity

was determined, and the team was set to develop preliminary design plans, a phase completed by

the end of December, 2014. With all necessary resources available, starting from January 2014,

Team Lancer Parking Solutions has been preparing engineering design plans for the project. The

project has been divided into smaller parts and each team member is responsible to carry out the

design for that specific part. Although each team member has their specific assignments, team

members still consult each other since all design portions are interdependent and significantly

connected. Towards the project closing phase, all design parts will be put together to develop a

single comprehensive design deliverable. This document in particular discusses the structural

design phase of the structure as well as the foundation.

Project Site:

After careful evaluation of the available space in the CBU campus and future expansion projects,

team lancer parking solutions with assistance from the CBU’s/ Facilities and Planning

Department the project site was selected. This parking structure will be located on a 3.05 Acre

site located within the CBU campus, between the CBU-recreation center, Diana Avenue, Lancer

Arms, and the future main campus drive located right in front of current facilities department

garage. The project site has a length of 535 ft and a width of 255 ft. The project site is depicted

in Google-Maps snip-shots below.

Proposed Structure

To a large extent, the shape of this structure will be of a parallelepiped composed of five levels.

Each level will have a long span of 530 ft and a short span of 230 ft, series of columns, beams,

shear walls, safety barriers, and ramps. The structure will have a design capacity of over 2200

vehicles, and will be equipped with all necessary installments to make it user-friendly . The

dimensions and components of the structure were chosen to optimize the land use and minimize

the number of levels of the structure, in order to meet the users and clients needs through a safe,

constructible and cost-effective design. The structure will be constructed out of cast-in place

concrete with embedded reinforcement bars, with section properties varying depending on the

member’s expected loading conditions. Cast-in place concrete was selected after deliberate

evaluation of possible structural materials, as depicted in the comparative tables below.

Table 1:

Material Advantage Disadvantage

Cast In Place ● Monolithic Construction

● Large Column Spacing

● Low Maintenance Cost

● High Construction Cost● Long Construction Schedule

Pre-Cast ● Quality Controlled● Lower Construction

Cost● Short Construction

Schedule

● Failure at Joints● Frequent Repair Work

Steel ● Flexible Column Spacing

● No Shear Walls● Shorter on-site

Construction● Lower Construction

Cost

● Risk of Corrosion● Fire Risks

Table 2:

As shown in table 2, Cast-in place came out with the highest grade hence being chosen as the

construction material for project.

Design Criteria:

At the end of the design phase, each structural member as well as the building as a whole will be

designed to bear the live loads( Floor live loads as well as roof live loads), earthquake loads,

wind loads, rain loads as well as the self-weight of the joint members. In developing the

structural model it was highly crucial to follow several design codes and specifications such as

AASHTO, ASCE, ACI, California Building Code, etc. Aside sticking to the available manuals,

in the design. I made sure to develop a facility that will be user-friendly, cost-effective and

constructible as mentioned earlier.

Structural Design Process:

The structural design part of this project was carried out as a systematic and iterative process that

involved (will involve) the following steps:

I. Identification and structural assessment of intended use and occupancy of the

structure

II. Development and structural assessment of architectural plans and layout

III. Estimation and characterization of structural loads

IV. Identification and development of structural framework

V. Analysis of the structure to determine members and connection design forces

VI. Design of structural members and connections

VII. Engineering reasoning the design outcomes

VIII. Inspection and approval by Professional engineers

In this document I will provide detailed discussions on how each step was (will be)carried on.

I. Identification and structural assessment intended use and occupancy of the structure

Throughout several meetings held with the client, CBU represented by Mr.Steve Smith, Mr. …..

I was able to develop a clear understanding on the use and occupancy of this structure from a

structural designer’s point of view. As mentioned earlier, the structure will be used to

accommodate 2200 vehicles of visitors, students, staff and faculty. The primarily objects in this

structure will be vehicles (Passenger cars, and buses on the first level), bikes, elevators, air

conditioning and electric equipments, as well as marketing panels. This information helped

predict various type of loadings, with a huge proportion categorized as both dynamic and static,

which lead to the use of both the AASHTO and ASCE design codes. These manuals and

information provide assistance in developing a model for a structure that will ensure the safety

and serviceability of the structure, i.e., designing the structure to carry the loads safely.

II. Development and structural assessment of architectural plans and layout

A collaborative effort with the lead-architect, Miss. Alejandra Gastellum, deep analysis of the

architectural plans were carried out, for a design that is structural feasible, cost-effective and

constructable. In charge of the structural design, I proposed several modification to the original

architectural plans in order to minimize structural components that would result into wasteful

expenses during the construction phase. Additionally, ASCE-7, and AASHTO codes were used

to select ramp slopes, maximum distance between columns (span length), minimum height

clearances,etc.

Below is a summary of the conclusion from the analysis of architectural plans:

● The structure was decided to be of a parallelepipedal shape.

● The structural will be largely symmetric,

● XXXXX Longitudinal bays,

● One ramp per level (level 1, level 2, level 3, level 3, level 4)

● Open top-on the 5 level

● A structural wall at least up to the third level on Diana Avenue

● Agreements on dimensions ranges of structural members (Details in forthcoming

sections)

(For additional architectural details consult Ms. Alejandra Gastelum).

III. Estimation and characterization of structural loads

Meetings with Mr. Suhail Farah and Miss. Danielle Lynch helped me obtain detailed and

relevant information about the possible loading conditions of the structure. Throughout the

discussions five categories of possible critical loads were developed.

- Live Loads:

Also called imposed loads, include all temporary and moving loads on the structure. In the

structural analysis/ design process, these loads will involve considerations such as impact,

momentum,, vibration, fatigue, etc. Below is a table that describes the live loads input used in the

structural analysis.

Table 3.

LIve load per floor 6623400 lb/floor UnitsSurface Pressure PsF SAP 2000

5th level 7198.26113207547 50 PsF4th level 14396.5222641509 100 PsF3rd Level 21594.7833962264 150 PsF2nd Level 28793.0445283019 200 PsF1 st Level 35991.3056603774 250 PsF

- Dead Loads:

This category includes all loads that are relatively consistent over time. These also include the

weight of the structure itself, and all immovable fixture such as architectural adds-on ( Walls,

plasterboard, etc.). Due to the type of possible dead loads,in the design most of the dead loads

will estimated by linking them to the density and quantity of the construction materials.These are

usually considered as gravity loads in structural design.

- Wind Loads:

These are due to the action of wind on the exterior of the building. In the structural design these

loads were considered responsible for possible lateral movements of the structure. Additionally,

in the design process I kept in mind that when wind passes over relatively flat surfaces, it applies

an upward load or suction, a phenomenon that is likely to occur on each level of this parking

structure. Wind loads are usually in form of pressure or suction on the exterior surfaces of the

building. Below is a table that describes the wind loads input used in the structural analysis.

Wind Loads Loads per Side(lb) SAP 2000-Inputs UnitLancer-Arms(WindWard) 347271.51 377.412056150943 PSF

Rec-Center(LeeWard) 216265.34 235.035539320755 PSFDiana Ave(SideB) 141686.55 153.983873207547 PSF

Main Campus (Side A) -141686.55 -153.983873207547 PSF

- Rain Loads:

As recommended by ASCE 7-02, section 10, each section of the roof will be designed to sustain

the load of all rainwater that will accumulate on it if the primary drainage system of that portion

is blocked plus the uniform load caused by the water that rise above the inlet of the secondary

drainage system at its design flow. These recommendations were/will be taken into consideration

in the design of this parking structure. Rain loads will be applied as a distributed gravity load

which typically causes the structural members to go under bending moments, shear forces, and

axial forces.

-Earthquake/Seismic Loads:

These loads result from rupture of prestressed tectonic plates, which generally manifest in rapid

movements or vibration of structures. In the structural design the earthquake loads were

characterized dynamic, and variant with the height of the structure. The effect of these loads can

be controlled by appropriate foundation design, structural stiffness, and the type of connections

used in the structure. This parking structure will be designed to resist the horizontal component

of the earthquake loads since there are generally weaker vertically in our region.

Earthaquake LoadsLoads per floor(lb) SAP 2000 unit

5th level 3274699.061 24.7147098943396 PsF4th level 2240077.644 16.9062463698113 PsF3rd Level 1522775.683 11.4926466641509 PsF2nd Level 835656.912 6.30684461886792 PsF1 st Level 0 PsF

Earthquake forces in Y-Direction Earthquake forces in X-Direction

IV. Identification and development of structural framework

This is a critical stage for the entire project. It is a process that must be both creative and

technical process, and requires fundamental knowledge of material properties and mechanics,

knowledge of various types of structural forms and configurations, as well as familiarity with

modeling computer softwares...AutoCAD 3D was used in this project. In order to carry out this

process, architectural plans were carefully analyzed to best understand the potential placements

of structural members. My expertise developed through engineering training from the Structural

Design class offered by Dr. Jong-Wha Bai at CBU, data from local parking structures and

insights from various practising engineers assisted me in developing a structural frame that will

be both cost-efficient for the owner, structurally safe for the users and easy to construct for the

contractor.

As mentioned earlier, the architectural plans proposed a parallelepipedal shape for the parking

structure. Using the structural expertise this rectangular solid was translated into structural model

composed of series of columns and beams, shear walls, slabs, and ramps all joined together, and

the whole assembly sits on a foundation. At every stage of developing the frame, the structural

designer had several options to chose from, and engineering judgement was used to pick the

most practical option. The selected/developed structural frame included moment resisting

frames, braced frames, dual frames, shear wall frames, and so on.

In the design my intentions were to develop a structure that will be user-friendly and that will

best accommodate the clients needs while meeting the recommended building codes and

standards. Hence, all viable material & framing plan alternatives were considered and designed

to compare individual material and fabrication/erection costs and the most efficient economical

framing system was selected. The following dimensioning characteristics were selected as

tentative using engineering judgement, however, they are susceptible to chances and will later be

calibrated to best meet the project’s specifications for the design deliverables.

- Longitudinal Bays (Magnolia-Indiana):

* Number of bays:

* Distance between Columns

* Number of slabs/levels:

* Number of Entrances:

* Number of Shear Walls

- Latitudinal Bays: ( Adams-Monroe)

* Number of bays:

* Distance between Columns

* Number of slabs/levels:

* Number of Entrances:

* Number of Shear Walls

-Level 1:

* Foundation Dimensions

* Level Max Height

* Number of columns

* Number of beams

* Shear Walls

-Level 2, Level 3, Level 4

* Slab Thickness Dimensions

* Level Max Height

* Number of columns

* Number of beams

* Shear walls

-Level 5:

* Slab Thickness Dimensions

* Level Max Height

* Number of columns

* Number of beams

* Shear walls

-Ramps (Tentative ):

* Dimensions

* Location:

* Material Properties

-Beam/Flexural members (Tentative ):

* Dimensions:

* Material Properties:

* Reinforcement:

-Column/Compression members (Tentative ):

* Dimension


* Reinforcement:

- Shear Walls (Tentative ):

* Dimension


* Number and location

-Foundation (Tentative):

● Soil Bearing Capacity

● Earthquake resistivity of the soil

● Underground utilities

● Design dimension selection

● Calculations/design procedure:

● Pictures from the DESIGN CODES

● Design Sectional Dimensions ( input)

● Selected Sectional Dimensions ( Output) [describe, explain why selected)

-Connections/Joint restraints:

* Beam-Columns

* Column-foundation

V. Analysis of the structure to determine members and connection design forces

* The structural analysis and design will be done using SAP 2000, a three dimensional based

structural engineering tool.

Description of the SAP2000

SAP2000 is a general purpose finite element program which performs the static or dynamic,

linear or nonlinear analysis of structural systems. It is a powerful design tool to design structures

following AASHTO specifications, ACI and AISC building codes. These features, and many

more make SAP2000 the state-of-the-art in structural analysis program, thus our choice to use

this program in the structural design of this project. SAP2000 will be used to model, analyze,

design, and display the structure geometry, properties and analysis results. Although the outputs

of this software are highly reliable/accurate, additional hand computations will be performed to

evaluate the accuracy of SAP2000 analyses and designs

The structural analysis/design process will be carried on in three phases:

1. Preprocessing.

2. Solving.

3. Postprocessing

Part I. Preprocessing.

In preprocessing, engineering judgement was used to make choices regarding the following

information which is needed by SAP2000.

1. Choosing the units for this project: We chose to use the US Customary Units

[ Pounds, Feet, Seconds]

2. Setting up the structure’s geometry: This step was carried on by importing the

3D structural frame developed using AutoCAD 3D as described in the previous

section.

3. Defining material and member section properties: As mentioned earlier, the

building will be developed using cast-in place reinforced concrete. The tentative

member section properties were chosen as results of the structural designer’s

expertise, data from local parking structures, and suggestions from various

professional engineers such as T & B Engineering, Inc.

4. Assigning member section properties and element releases.: This was directly

done through SAP2000 graphic user interface as described in the snapshots

below:

5. Defining load cases: As discussed earlier, we will have two types of loading

conditions acting on this structure: Static loads and dynamic loads. The estimated

types of loadings were combined in the following several different cases of load

combinations. This step was completed done directly through SAP2000 graphic

user interface as described in the snapshots below:

6. Assigning load magnitudes.: This step was completed directly through SAP2000

graphic user interface as described in the snapshots below. The loads used in this

process are those previously discussed in section III.

7. Assigning restraints: this step was completed done directly through SAP2000

graphic user interface as described in the snapshots below. The structural engineer

chose……… restraints,a commonly used type of joints in cast-in place concrete.

From experience, I found out that it is very important to assign restraints to the

structural model otherwise your structure will become unstable or it becomes

a free body and it cannot be solved by SAP2000.

PART II. Solving

During this phase SAP2000 will assemble and solve the global matrix. The following steps are

needed: Below is a step-by-step description of interactions with SAP2000 performed to carry on

this process.

1. From the Analysis menu, Set Option was selected… This displayed the Analysis Option

dialog box.

2. In this dialog box, the appropriate DOF was selected, and then clicked OK.

3. From the analysis menu, I select Run. The Save Model File As dialog box was then

displayed to allow saving the file.

4. After specifying where the file should be saved, the analysis began. A top window was

opened in which the various phases of analysis process are progressively reported. When

the analysis is complete, the screen will display the message "ANALYSIS COMPLETE".

Below is the description of this process through Snapshots.

PART III. Postprocessing.

In this phase of structural analysis and design, SAP2000 will help provide the following

details/options:

1. Displaying the deformed shape of the structural model under the assigned loading

conditions.

2. Displaying the forces in each structural member:

3. Printouts of the analysis and design results.

4. Designing the structural members and checking the safety of a design.

5. Modifying the structure.

Briefly, after the analysis is complete, SAP2000 automatically displays the deformed shape of

the model for the default load case, LOAD1, in the active display window. The double view

windows in SAP2000 enables us to display the deformed shape for two load cases, which allows

to make comparative analysis. The display of the deformed shape provides details such as the

member force diagram box by selecting the component being analyzed...i.e. by moving the

cursor to a specific location we can read the values of the forces at that point. As mentioned

earlier, SAP2000 can use the analysis results to design appropriate structural members. SAP2000

is equipped with information about the updated codes and specification, these can/will be used to

check the safety level of the structure. In fact, SAP2000 will suggest various design options for

the structural members properties, and engineering judgement will be used to select the most

appropriate design to meet the previously discussed design criteria.

VIII. Foundation:

● Soil investigation:

○ Soil Bearing Capacity

○ Earthquake resistivity of the soil

○ Underground utilities






IX. Deliverables:

● Detailed Construction drawings of typical beam

● Detailed Construction drawings of typical column

● Detailed Construction drawings of typical slab section

● Detailed construction drawings of typical ramp section

Conclusion:

● Reintroduce the project’s objective

● Discuss the challenges encountered

● What recommendations?

● What did I learn?

V. Defining load cases.

Now, it is time to give SAP2000 the applied load’s information. The steps are:

1. From Define menu, choose Static load cases… This will display the define load

case dialog box.

2. This dialog box will display the default load, LOAD1, with type set to Dead, and

self-weight multiplier set to unity. This will automatically include the self-weight

of structural members in the analysis based on preset specific weights given in

function of the material type. We don’t have to change anything for this first load

case. But if you wish to enter the weight by your self and put it as joint load, or if

you went to ignore the offset of the dead weight, then you should change the self-

weight multiplier to 0 to avoid count the self weight twice.

3. Define additional load cases, change the LOAD1 to LOAD2 (or the case you

defined), select load type from the Type drop-down list box, change the self-

weight multiplier to appropriate number. In most times, you change the self-

weight multiplier to 0 because dead load already count dead load in LOAD1).

Then click on the Add new Load button to notify SAP2000. Repeat this step until

you define all the load cases.

4. Finally, click OK to back to main window.

In the following section of assigning joint load cases, you must assign a numerical volume and

the location of each joint loads for every load cases.

VI. Assigning loads.

For simplicity, we just talk about assigning joint loads. If you wish to apply a distributed load on

a member, you can refer to SAP2000 manual for detail. To assign joint loads execute the

following steps:

1. Select the joints which have the same joint loads. You can use one of the three

selection methods used previously to select members.

2. From the Assign menu, choose Joint Static Loads, then Forces… from the

submenu. This will display the Joint forces dialog box.

3. In this dialog box, accept the default load case name as LOAD1, enter the

corresponding joint force components in the Load area. Click OK to accept the

above joint loads.

4. Repeat steps a, b and c until you assign all the joint loads of this load case defined

to this structure.

5. Repeat steps a, b, c and d until you finish every load case’s load assignment.

VII. Assigning restraints.

It is very important to assign restraints to your structure. Otherwise your structure will become

unstable or it becomes a free body and it cannot be solved by SAP2000. Applying joint restraints

requires the following steps:

1. Click the Pointer Tool button ( i.e. ) in the Floating Toolbar.

2. Click the joints which have the same restraints.

3. From the Assign menu, choose the Jointà Restraints… from the submenu. This

will display the joint restraint dialog box.

4. In this dialog box, choose appropriate restraint parameter. Then click OK to

accept this assignment.

5. Repeat steps a, b, c and d until you finish the restraint assignment.

PART II. SolvingIn this part SAP2000 will assemble and solve the global matrix. The following

steps are needed:

5. From the Analysis menu, select Set Option… This will display the Analysis Option

dialog box.

6. In this dialog box, check the available DOF. If you are analyzing a plane truss, check UX

and UY, leave the UZ, RX, RY and RZ blank.

7. Click OK to accept what you choose.

8. From the analysis menu, select Run. This will display the Save Model File As dialog

box.

9. In this dialog box, save the model under a filename. No extension is necessary.

10. Click the OK button, the analysis will begin. A top window is opened in which the

various phases of analysis process are progressively reported. When the analysis is

complete, the screen will display the message "ANALYSIS COMPLETE".

11. Click OK button in the top window to close it.

PART III. Postprocessing.

The main options in post processing are:

6. Displaying the deformed shape.

7. Displaying the member forces.

8. Printing the results.

9. Designing the structural members and checking the safety of a design.

10. Modifying the structure.

For simplicity, we just discuss the three fundamental options: displaying the deformed shape,

displaying the member forces and printing results here.

1. Displaying the deformed shape.

After the analysis is complete, SAP2000 automatically displays the deformed shape of the model

for the default load case, LOAD1, in the active display window. We can now display the

deformed shape for another load case in one of the two view windows.

1. Activate one of the two view windows by clicking anywhere inside that window.

2. Click the display deformed shape button on the floating toolbar. This will display the

deformed shape dialog box.

3. In the drop down list in the load area of this dialog box, select the load case to be

displayed, then click OK button. The deformed shape will show.

1. Displaying the member forces.

1. From the Display menu, click the Show element forces/stressesà frames, this will

display the member force diagram dialog box.

2. In this dialog box, select the component which need to display (for truss, choose Axial

force) in the Component area, and click OK button. The axial force diagram for the

entire truss is displayed. By moving cursor to a specific location, we can read the values

of the force at that point.

1. Printing the results.

1. From File menu, select Print Output Table… In the display dialog box, click OK to

accept the default setting. The detailed output results will be printed.

2. From File menu, select Print Input Table… In the display dialog box, click OK to

accept the default setting. The detailed input information will be printed.

You can also get the detailed results in another way. When we analyze a structure, by default,

SAP2000 will create three output files: filename.out, filename.log and filename.EKO. The output

file filename.out stores the output of your analysis. The output file filename.EKO stores the input

information for this structure. The output file filename.log take all of the running information.

These files are text files. You can print these files using computer operating system. For

example, we can print these files from Notepad. The steps are:

1. Open Notepad by double click the Notepad icon on the main window.

2. From File menu, choose Open. This will display a standard Microsoft file

selection dialog box.

3. In this dialog box, choose the drive and subdirectory where your file is located.

4. Click on the file name you want to display and print. (i. e. any one of

filename.out, filename.EKO, or filename.log.)

5. Click OK to terminate this dialog box. Your file will display by Notepad.

6. Review the file to make sure your results are correct.

7. From File menu, choose print… This will display the print dialog box.

8. Click OK to accept the default print setting. Your file will print on background.

9. Repeat steps b, c, d, e, f, g and h to print another file.

10. Close Notepad by choosing Exit from the File menu.

○ INPUTS:

■ structural frame model

■ loads

○ OUTPUTS:

■

● LOADS:

○ Load Combinations:

○ Load assignment:

■ Live loads

■ Dead Loads

■ Earthquake Loads

■ Rain Loads

■ Wind Loads

● OUTPUTS:

○ Moments

○ Axial Forces

○ Lateral Forces:

● SELECTION OF APPROPRIATE DESIGN OPTION

○ Design for Strength

○ Design for Constructability

○ Design for a reasonable price

● DEVELOPMENT OF CONSTRUCTION DRAWINGS

Critical Design Parts:

I. Columns:

● The parking structure will have three series of columns. The exterior columns, the inner

columns, and the ram bearing columns. Based on ASCE-7, section XXXXX every

section of long span will be composed of __(# of columns)_Columns. This number was

determined by dividing the span length and the assumed column spacing of XXXXXX

with is equivalent to three parking spots. For design purposes, each column was assumed

to be of XX ft by XXXX ft. These dimensions were picked based on ACI

recommendations as well as observation data from several parking structures visited

around in Southern California. Each of these columns will be made out of cast-in place

concrete, reinforced with steel rebars as mentioned earlier. Further down, a discussion

will be given on how the appropriate design column size; reinforcement bars’ size,

number, placement; concrete’s properties, as well as other design options are developed

and selected. As mentioned earlier, the structure will be composed of 5 levels. The

columns sections in first level will have a height of XXX ft. This design height was

selected based on AASHTO minimum clearance for emergency vehicles, buses and

handicap vehicles that will be housed in the first level of the structure. Columns sections

in the second, third, and fourth floor will have a height of XXX ft... The columns sections

the fifth floor were designed to have a height of XXX ft ...

● Columns design procedure

● Calculations




II. Beams:


● Beam design procedure

● Calculations:


● Design Sectional Dimensions sketch ( input)


III. Connections:

● Type of connections ( why they were chosen)

● Design in SAP2000

● Connection design equations

IV. Slabs:


● slab design procedure

● Calculations:




V. Ramps:


● slab design procedure

● Calculations:




VI. Stairs:

● Design dimension selection/how manny?

● Beam design procedure Calculations:




VII. Shear Walls


● Calculations/ Design procedure




VIII. Foundation:

● Soil investigation:

○ Soil Bearing Capacity

○ Earthquake resistivity of the soil

○ Underground utilities






IX. Deliverables:

● Detailed Construction drawings of typical beam

● Detailed Construction drawings of typical column

● Detailed Construction drawings of typical slab section

● Detailed construction drawings of typical ramp section

Conclusion:

● Reintroduce the project’s objective

● Discuss the challenges encountered

● What recommendations?

● What did I learn?

Technical memorandum -Senior Capstone Project

Engineering

Transcript of Technical memorandum -Senior Capstone Project