HISTORIC STRUCTURE

Historic structures

significant structures of the past

Ross Island Bridge

By Frank Griggs, Jr., Dist. M.ASCE, D.Eng., P.E., P.L.S.

Dr. Frank Griggs, Jr. specializes in the restoration of historic bridges, having restored many 19th Century cast and wrought iron bridges. He was formerly Director of Historic Bridge Programs for Clough, Harbour & Associates LLP in Albany, NY, and is now an Independent Consulting Engineer. Dr. Griggs can be reached at fgriggsjr@verizon.net. Gustav Lindenthal, a leading proponent of continuous bridges, finished his Sciotoville Bridge (STRUCTURE, May 2017) in August 1917. In late 1922, a call went out to the largest and best-known engineers of the country to design three bridges (the Burnside, Ross Island, and Sellwood) across the Willamette River in Portland, Oregon. A group consisting of Ira Hedrick and Robert Kremers (Kremers was the local connection and had previously worked as an Engineer for the City) was awarded the contract to design the three bridges. Hedrick had been in partnership with J. A. Ross Island Bridge. Courtesy of HAER. L. Waddell up to 1907 when he went on his own. When announced, the local newspaper in the Engineering News-Record, to which the wrote, under the headline Good Team to Build Strong & McNaughton Trust Co. had called Bridges, “By awarding the contract for engineer- my attention in their telegrams, I thought the ing on the Burnside and Ross Island bridges to matter important enough to assist you with any Hedrick and Kremers, the county commissioners professional advice I could give. The telegrams have lived up to their pledge to cover all that needs to be said at present in a employ a local engineer and business way.” at the same time have secured Hedrick’s design for the Ross Island Bridge was the services of an engineer of for “six reinforced concrete arches of 267 feet span wide experience with large rising to 135 feet above the river, joined on each structures of the kind proposed side by approaches of the girder and post type and of high reputation.” and with a total length of 4,122 feet, including By early 1924, Hedrick and Kremers had a fill 400 feet long.” designed concrete bridges for Ross Island and Lindenthal’s report came out on July 7, 1924, Burnside, and planned to reuse parts of the exist- with the Oregonian headline, Dr. G. Lindenthal ing Burnside Bridge to build the Sellwood Bridge. to Build Bridges, County Board Ousts Hedrick Bids were called for in March for the Ross Island. and Kremers from Job, Change in plans urged, Three bids were received with the Pacific Bridge Revised Structures for Sellwood and Ross Island Are Company coming in low at $414,000, well below Considered by Engineer. The paper then printed the second bidder, the Missouri Valley Bridge excerpts from Lindenthal’s report, calling him & Company. On the Ross Island Bridge, only “the world’s greatest engineer.” After indicating one bid came within the estimate. Hedrick and that Hedrick and Kremers would receive another Kremers recommended that the bids should be $25,000 for their work, it reported Lindenthal rejected and the work re-advertised. had been awarded a contract for a major redesign The Commission voted to accept the tainted of the Ross Island Bridge as well as the other two bids, which resulted in political turmoil. A bridges. His contract was for $119,000 for the recall election was held, and three members three designs and supervision of construction, and of the County Commission were removed was signed on July 11, 1924. On November 4, from office for gross irregularities in the bid- 1924, the County voters approved an additional ding on the bridge. A new board was elected. $500,000 for the bridges. This new Board had little trust in the team of In his report, Lindenthal told the board that Hedrick and Kremers and began looking for an there were four conditions to ensure a bridge was engineer of national reputation to advise them appropriate and adequate. They were “Location, on the designs of the bridges. They contacted Traffic Capacity, Structural Character, and, for Lindenthal, who initially did not want to get a city bridge, the Architectural Features, in the involved in what was becoming a political free order named.” Lindenthal stated, regarding the for all. He eventually relented and wrote, “Just Ross Island Bridge, “I recommend that the plans for the record, I beg to enclose copies of tele- for this bridge be entirely redesigned for the folgrams received and sent in the matter of the lowing reasons: proposed examination of plans for the three 1) It is doubtful whether the bridge on the bridges named therein. I confess that I first present plans could be built within the felt disinclined to undertake this long trip in amount appropriated for it. the midst of pressing engagements, but after 2) The borings in the river bottom indicate reading the account of your bridge situation an irregular stratification of sand and

gravel which, in my judgment, does not offer sufficient security against the uneven settlement of the pier foundations proposed to be sunk by the air process. A slight settlement which would not endanger a low structure may be enough to seriously endanger high piers and high concrete arches which require a greater degree of safety for their foundation. No chances should be taken with the foundations for high concrete arches. 3) The axis of the bridge should, if possible, be on a straight line and for better appearance, the hump in the roadway over the river hold be taken out. For that purpose, the clear height over the channel should be reduced 135 feet to about 80 feet… I am informed that an act of Congress authorizing such lowered height will be necessary, but that it can be obtained without much delay when desired by the people.” A notice to contractors on the completely redesigned Ross Island Bridge went out on April 25, 1925, and bids were due back by May 18, 1925. The central span was 535 feet with the two 321-foot flanking spans on each side. Simple girder deck spans formed the long approach viaducts on each side of the river. The central three spans were continuous over four supports. The outer flanking spans were simply supported trusses, 321 feet long. The total length of the bridge was 3,649 feet with a deck width of 43 feet. The fixed bearing was on the right side of the central span with the others being expansion bearings. The bridge was on a vertical curve with the grade on the approach spans on each side being 2.5%. The four flanking spans were built on falsework. Each half of the long center span was built out as a cantilever and connected at the center by a pin. Under dead and full live load, they acted as two determinate cantilevers, similar to the Queensboro Bridge. In fact, some commentators called this an inverted Queensboro as it also didn’t have a suspended span. Under unbalanced live load, the bridge acted as a fully continuous bridge, and the member loading was determined using elastic methods. The steel was fabricated by the American Bridge Company and was erected by Booth and Pomeroy, Inc. It opened December 1, 1926, at the cost of just less than $2,000,000. It was completely rehabbed in 2002 at the cost of $12,500,000. A cable-stayed bridge just upstream, the Tilikum Bridge, was opened in 2015. Lindenthal’s Sellwood bridge, built at the same time, was a continuous bridge over four spans. The two interior spans were 300 feet long, and the flanking spans were 246 feet long. It carried two lanes plus a sidewalk over the Willamette River. Its cost was $541,000. It was replaced in 2016. These two bridges, plus the Burnside Bridge (a bascule span) were the last bridges Lindenthal worked on, even though he continued to promote his Hudson River Bridge until his death in 1935. In the July 1932 issue of Civil Engineering Magazine, Lindenthal wrote an article entitled, Bridges with Continuous Girders, Reviewing Half a Century of Experience in American Practice. In it, he gave a summary of his efforts over the years to promote continuous truss bridges. He was 82 years old at that time and still contributing to the literature of bridge building. Lindenthal was rightfully called the Dean of American Bridge Builders.▪

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Professional issues issues affecting the structural engineering profession Compensation, Overtime, and the Gender Pay Gap

Structural Engineering Engagement and Equity (SE3) Committee Survey Results

By Angie Sommer, S.E. and Nick Sherrow-Groves, P.E.

In Part 1 of this series (STRUCTURE, April 2017), the results of the 2016 SE3 Study focused on overall career satisfaction, development, and advancement. This article highlights survey findings regarding compensation, overtime, and the gender pay gap. A full report that includes findings on work-life balance, flexibility benefits, and caregiving can be found at SE3project.org/full-report.

Compensation

Respondents overall indicated that pay and compensation were the top reasons that they had considered leaving the structural engineering profession or leading reasons why they had left the profession. When asked to rate their satisfaction with pay/compensation, 20% of the respondents reported being “unsatisfied” or “very unsatisfied.” The average income of all respondents currently practicing structural engineering is $106,800 per year. Pay data were received from 1,955 respondents. Because nearly half of the respondents were from California, where the cost of living is higher than in most other parts of the country, income data for this group is noted separately. The average income of all of the respondents from California is $117,600 per year. As a snapshot of income during the careers of respondents, the average income of a structural engineer with five years of experience is $78,900 per year (in California, the average is $89,000). The average income of a structural engineer with 15 years of experience is $110,600 per year (in California, the average is $118,700). Pay data of the survey respondents is also shown in Figures 1 and 2. For this survey, “income” is defined as gross annual income, including bonuses. Note that the data includes part-time employees who work fewer than 40 hours per week, which accounted for 110 respondents (6%). Considering only full-time employees residing in metropolitan cities, respondents in California reported income 21% higher than those living outside California. However, when income is normalized to cost of living data (as reported by the Council for Community and Economic Research, http://coli.org), respondents in California make 7% less than those outside California.

Figure 1. Average income vs. years of experience (all respondents).

For comparison, nationwide data, collected by the U.S. Bureau of Labor Statistics (BLS) in 2015, show that the mean annual wage for a civil engineer in the “architecture, engineering, and related services” category was $88,820 (in California, the mean annual wage was $100,980) (BLS, 2016b). The BLS calculates “annual wages” by multiplying the hourly mean wage by a “year-round, full-time” figure of 2,080 hours. For those occupations where there is not an hourly wage published, the annual wage is directly calculated from the reported survey data. The BLS does not report information on structural engineers specifically. In comparison with the average income of all practicing survey respondents to the “mean annual wages” reported by the BLS, SE3 survey respondents reported approximately 20% higher income than the BLS data, some of which is likely due to the inclusion of bonuses in the SE3 survey responses. Additionally, SE3 data may be more highly weighted by California responses than BLS data. A 2013 Structural Engineering Institute (SEI) survey reported the average salary of respondents to be $85,500 per year, based on 728 responses from throughout the United States (Leong et al., 2013). This average salary also excluded bonuses and is therefore noted to be a similar finding to BLS data, especially considering inflation.

Figure 4. Income vs. years of experience (full-time only).

Figure 5. Average income by title and gender. A significant pay gap was reported between genders. Out of 1,401 men and 553 women who provided pay data, women reported making $27,500 per year less than men, on average, which amounts to women making approximately 75% of the salaries of their male colleagues. When controlling for years of experience and full-time employment, men still reported making significantly more money than women. For example, for full-time employees, men with 14-17 years of experience made $7,900 per year more than women, and men with 18-20 years of experience made $41,200 per year more than women, as shown in Figure 4. When broken down by position, a similar trend persisted, though the gender pay gap widened significantly starting at the senior engineer/project manager level. A $9,000 pay gap was present for senior engineers/project managers, a $12,000 pay gap was present for associates/shareholders, and a $52,000 pay gap was present for principals/ owners, as shown in Figure 5. Further analyses were performed based on a variety of factors (location, position, full-time employment, firm size, with/without children), and in all cases, the gender pay gap was found to exist. Additionally, because nearly half of respondents were from California, the gender pay gap within this state was also reviewed. The pay gap was found to be less pronounced in California as compared to the overall data set, but it was still present. The 2013 SEI survey found that the average annual salary for women was 78% of that reported by men. Similar to the SE3 data, the pay gap widened as the number of years of experience increased.▪

Hours Worked and Overtime

Angie Sommer is an associate at ZFA Structural Engineers in San Francisco, California. She is the primary author of the 2016 SEAONC SE3 Survey Report and is the 2016-17 co-chair of the SEAONC SE3 Committee. She can be reached at angies@zfa.com. Employees who work extra hours are more likely to consider leaving the profession. For each additional hour worked per week over 40, the odds of an employee considering leaving the profession were found to Nick Sherrow-Groves is a senior engineer at the San Francisco office of Arup. He is the 2016-17 co-chair of the SEAONC SE3 Committee and can be reached at nick.sherrow-groves@arup.com. be 4% higher. This points to a tendency for people to “burn out” when their workload is consistently over 40 hours per week. Additionally, satisfaction with pay and benefits was found to decrease as the number Connect Steel to Steel without Welding or Drilling of hours worked each week increased. Conversely, being compensated for over• Full line of high-strength, corrosion-resistant fasteners time is correlated with significantly higher • Ideal for secondary steel connections and in-plant equipment satisfaction with pay/compensation. Of • Easy to install or adjust on site the 1,629 respondents who responded • Will not weaken existing steel or harm protective coatings to this question, 46% indicated that they • Guaranteed Safe Working Loads receive pay for overtime and compensatory time for hours worked over 40 in one week, as shown in Figure 3. This group was 20% more likely to report being “satisfied” or “very satisfied” with their pay/ compensation than those who are not BoxBolt® for HSS blind connections. ICC-ES FastFit universal kits for faster, easier steel compensated for overtime. certified. connections. Interestingly, those who reported being compensated for overtime also reported working an average of two fewer hours per week than those who are not paid for overtime. Reasons for this were beyond For a catalog and pricing, call toll-free 1-888-724-2323 the scope of the survey. A KEE SAFETY COMP ANY or visit www.LNAsolutions.com/BC-2