A Beginner's Guide to Structural Engineering

Homework/Example Problem Structures

© 2007 T. Bartlett Quimby

Overview

Last Revised: 11/04/2014

One objective of this website is to introduce structural engineering students to the tools of the profession.  One of the tools that is fundamental to the profession is engineering drawings.  It is not uncommon for today's students to receive their first introduction to real drawings after graduation.  In an attempt to overcome this deficiency, the assignments for this text will come from three structures plus a handful of stand alone details.  This section introduces those structures. 

Each of the structures can be considered to be in the "schematic" phase of design.  This means that we have a fairly good idea of the structural configuration but are still working on member sizing and connection detailing.

The structures that will be designed in example problems and as homework problems are as follows:

• Dormitory:  A three story building frame that includes both moment and braced frames.  This structure was originally designed in the early 1980s but, for a variety of economic reasons, was never built.  This structure will provide many of the problems related to beams and beam-columns as well as a few axial force brace members.
• Tower:  A free standing communication tower that is loosely modeled after a recently constructed (2007) structure.  The design has been altered a bit to take advantage of some details found on other similar structures.  This structure provides a variety of axial force members and connections.
• Bridge:  An old truss style bridge built in the mid 1900s.  This easily analyzed structure includes a number of axial force and bending members to design. 
• House:  A simple two story wood framed home.  This structure was designed and constructed in the summer of 2007.

Click on the links for each structure to get a more complete description of each structure and to download the drawings.

Each structure has it's own, downloadable, drawing set that is referred to in the homework problems.  The drawing sets are located on the page devoted to each structure.  Click on the links above to go to them.

As no structure contains it all, there are sets of typical details for each material type.  Click on their links to download the files.

• Miscellaneous Details

Reading Engineering Drawings

It is expected that the student in this course has taken a course in engineering graphics and, consequently, will be able to figure out how to read the drawings.  However a brief review is given here.

Each drawing set includes plan views, elevations, sections and details of the structures.  The set also includes a section entitled "General Notes" that apply to the entire drawing set.  You will want to read those before getting to involved in the design.  There is also a sheet index.

In the case of the dormitory, there are both architectural and structural drawings.  The purpose of the architectural drawings is give you the overview of what the architect is trying to achieve.  The architectural drawing numbers all start with an "A".  The structural drawing numbers start with an "S".

Generally the overview plan and elevations are on the first sheets of the drawing set.  In the case of the dormitory building, there is a plan sheet for each level on different sheets.  Elevations for lateral force resisting frames follow.  A common practice is to introduce a grid system to make drawing reference easier.  This has been done on the dormitory building, which has a more complex geometry than the other structures.  A grid system on the tower is not useful.  The bridge is could use one but the simplistic nature of the doubly symmetric system make a grid system of marginally useful.  It has been omitted on the bridge.

On the plan and elevation drawings are a number of "cut bubbles".  These circles have a horizontal line through them with a detail/section number in the upper half and a drawing number in the lower half.  The lower number is the drawing on which you will find the indicated detail or section.  The upper number is the drawing on that sheet that has the detail or section that is indicated.  Coming off the circle is a line that either connection with an oval or circle or a line with heavy line perpendicular to the end.

The oval or circle indicated that you will find a larger view of what the oval or circle contains.  This is a "detail".  The line with the heavy perpendicular line indicates that the referenced drawing will show you a cross section of the structure that results from cutting the structure where the line is and looking in the direction indicated by the heavy line.

Spend some time reviewing the drawings until you are familiar with the structures.