Sunday, April 29, 2012

Sewell's Falls Bridge-The other Sister!



When I wrote the tale of two sister bridges, I did not have compatible photos of the Sewell's Falls Bridge. Today I happen to be in the area so I took  photos compatible to the earlier shots. Sewell's Fall Bridge is very similar to the Lilac Bridge in Hooksett. First the top chords form a horizontal line, they are at heart two span structures even though Sewell's Falls has an extended set of approach spans, the main spans are of compatible lengths, and the truss members appear to be identical with the same number of vertical and diagonal members. The Sewell's Falls Bridge was designed by John Storrs and constructed in 1915. It was also rehabilitated in 1936.  The face of the structure has very similar features including the pipe rail, horizontal supports of the portals and the rounded connections to the truss members. The portal framing is more open, but generally follows the same geometry. The biggest difference visually is the construction of the deck. Sewell's Falls currently has a steel grate deck where the other two bridges have wooden decks. I have called out to some of the long time residents of Concord to clarify whether the deck was originally wood. I also had a chance to look under the Sewell's Falls bridge. I think I mis-spoke on the earlier post. Visible from the top of both the Sewell's Falls Bridge and the Lilac Bridge are lateral joints every fifteen feet or so. I had previously assumed these were stringers that connected to beams that I had not verified from below. In fact it appears that these lateral members are actually the beams and the stringers that support the deck connect into the beams. Not being a bridge engineer by trade I will let my structural counterparts correct my structural vocabulary, but hopefully there articles will spur a few to go and visit these structures before they are gone. It would also be interesting to know more about the properties of the steel used in these bridges. The chemical make up of steel ordered today is of a consistency that engineers using the material can have a very high degree of certainty that the properties attributed to the product will in fact be true within an impressive tolerance. Prior to 1940 those properties had a lot more variance. By changing the chemical composition of steel, such as changing the carbon content, the strength and malleability (brittleness) of the steel can vary significantly. There are design guide books that can provide general guidance on the steel makeup based upon the year made and statistical probabilities, but for greater reliability samples of steel can be cut from the individual bridges being analyzed and tested to determine more accurate material properties. An added twist is that different members of a bridge may be built in different locations or that less critical members may have been made from different steel.

Saturday, April 28, 2012

A Tale of Two Sisters (Boscawen-Canterbury and Hooksett Lilac Bridges)

Recently there was an article on the planned removal of the Boscawen-Canterbury Bridge. This bridge was designed by John Williams Storrs and constructed in 1907. By 1965 it was decided to close the bridge to traffic as the original design was not compatible to the modern vehicles. This is a two span structure with a total span of about 347 feet. Assuming the spans are symmetrical, the individual spans would be about 174 feet. To the left is a profile view of one of the spans. Note the rounded appearance of the top chords.Storrs is
recognized as one of the first true design engineers in the region. When Storrs is mentioned the first example of his work  is normally the Sewell's Falls Bridge currently under redesign and slated for rehabilitation in the next few years, but there is another sister bridge in Hooksett that is also in a similar state of disrepair. 

The Lilac or Hooksett Village Bridge in Hooksett is a three-span high Pratt Truss also designed by Storrs. This bridge was opened in 1909 and repaired in 1936. In 1976 this bridge was bypassed and closed. The total span is 490 feet with the longest span about 170 feet. The remaining spans are approximately 160 feet. The horizontal alignment of the upper chords and the different scales on the pictures make these bridges look very different, but looking at other angles definitely shows the family resemblance.

Here is a picture of the front of the Boscawen-Canterbury bridge. The curved shape of the upper chords results in a shorter distance between the horizontal members of the portals, but otherwise the geometry of the truss members appears to be identical, member sizes are close, and the portal bracing is also very similar. I could not get a good view of the connections now that both bridges are closed to pedestrian traffic, but assuming these are simple connections, the spans of the bridges are very similar. The pipe railing is also used on both bridges even though on the Boscawen-Canterbury bridge the pipe railing on the right side is now detached and draped across the deck. Also note the curved molding detail where the portal and truss meet on both bridges. Unfortunately one other thing that both bridges have in common is the passage of time, a number of years being out of service and little or no hope of being rehabilitated before being turned into scrap metal before anyone raises a serious effort to preserve them.It is unfortunate that when a bridge is tagged with a historic designation it actual further encumbers the engineers that are trying to save it. Bridges not being repaired for lack of funds require even more money when the bridge has been identified as historical. In the end the engineer and historic nature of the structure are put at odds due to the higher costs and longer time lines required for design and construction. If we truly value our historic bridges, we need to make it an advantage to have a historic bridge designation when setting priorities for funding.

Currently bridges are rated between 0 and 100 with new bridges rated higher and these two bridges rated at or near zero. As bridges deteriorate, they become eligible first for rehabilitation funding and if allowed to deteriorate further then they become eligible for replacement funding. An idea would be to identify bridges that are culturally more significant and make those structures eligible for these funding sources 10 rating points or more prior to other bridges. Since many of our historic structures are already well past their ratings needed to be eligible for funding, the other consideration would be eligibility for funding. Many of these structures are no longer the work horses of our transportation systems and do not rise to the priority of the more heavily traveled structures. This will continue to occur by necessity while we systematically underfund our transportationinfrastructure.

The top deck photo is from Boscawen-Canterbury. The pipe rail is now rolled over onto the deck. Below is the Lilac Bridge deck. Again note the similarity in the truss members and portal framing. A noticeable difference is the sidewalk on the left hand side of the Lilac Bridge. A careful eye will also spot the cradles for what was either a gas or water line that has since been removed. Both decks were wooden, but the Boscawen-Canterbury bridge had longitudinal decking running continuously over what looks like steel lateral stringers. The Lilac Bridge has lateral decking with a steel member every 15 feet. The decking system would be more apparent with a view below the bridge, but it didn't happen this trip.

For both of these bridges I am afraid that time is running or has run out. If you value historic structures, grab your camera and get out for a visit. For many of these structures, recognition of their historic value to the extent where funding will be provided in time to save them will never occur before the only option will be documentation then scrap metal. Engineers are a practical lot. I would be interested to know what John Storrs would think about the historic preservation requirements and attempts to save his bridges, of which I believe only seven are still in existence.



Cape Air suspends flights during airport upgrade: Rutland Herald Online

Cape Air suspends flights during airport upgrade: Rutland Herald Online

Only In Print: Development plan gets city businesses excited | New Hampshire NEWS15

Only In Print: Development plan gets city businesses excited | New Hampshire NEWS15

Where the trail ends: now a bridge | New Hampshire NEWS

Where the trail ends: now a bridge | New Hampshire NEWS

Disappointing proposal on future of Postal Service | Concord Monitor

Disappointing proposal on future of Postal Service | Concord Monitor

Concord: Deal for bindery done | Concord Monitor

Concord: Deal for bindery done | Concord Monitor

Sunday, April 22, 2012

Northeast Regional Concrete Canoe Competition held at UNH

This Friday and Saturday UNH hosted the ASCE Northeastern Regional Concrete Canoe Competition. Eleven schools competed for the honor of representing their region at the National Competition to be held this summer in Las Vegas. The competition includes a design report, graphic display, oral presentation, scoring of the aesthetics and workmanship of the canoe, and finally the race competitions.

Schools included Worcester Polytechnic Institute (WPI), Wentworth Institute of Technology (Wentworth), Northeastern University (Northeastern), University of Massachusetts-Dartmouth (Dartmouth), University of Rhode Island (URI), University of New Haven (New Haven), University of Massachusetts-Amherst (Amherst), University of New Hampshire (UNH), University of Massachusetts-Lowell (Lowell), University of Maine (Maine), and Universite Laval (Laval) .

Anyone who has proposed on a qualifications-based selection would have a good idea on the expectations for the design report. There are very specific rules on the page limitations, order, and specifications. Reports are rated based upon the executive summary,  structural analysis, test and development, construction, project management, sustainability, innovation, concrete mix design, and the overall report presentation.

Graphic displays included a cross section of the boat and a product display. These were graded based upon a list of specific items and displaying them with a marketing-style flair. The schools generally wove a common theme throughout the materials including the boat name, display, exterior finish of the boat and written and oral presentations.

Oral presentations were graded on the performance of the presenters, quality of the presentation, and ability of the presenters to answer questions from the judging panel.

 To provide better understanding of the competition, it is important to know the diversity of the entries, and the thousands of hours dedicated to these projects. Laval was a top five finisher in last year's national competition. They are dominant in all facets of the competition. From the polar bear supporting their canoe, igloo-shaped display, dog sledding scene inside the canoe, and expert canoeing skills, they set the bar for the Northeast competition. Unique to the competition is their shot-crete technique using a specially designed applicator, allowing them to meet a 1/2" hull thickness. They had the lightest canoe while maintaining one of the strongest mix designs.

 Lowell wove into this year's canoe a theme of their city's strong industrial roots. The picture shows their canoe support fashioned in the style of their historic mill districts and the art on the canoe matching the cogs that ran their machinery. With Laval's top five finish in the previous year's national competition, the rules allow for a second competitor to also attend the nationals from the Northern region. Lowell early in the competition put in their bid for one of those coveted two slots to Nationals, but with a strong field, it was all going to come down to the critical races which make up 25% of the overall score.

Maine has a history of strong showings in the Northeastern region. This year their boat performed particularly well on the water. They also had the most dominant cheering section providing renditions of school songs as their paddlers negotiated the courses. It is only natural to see Maine and UNH compete against each other as they have healthy rivalries in almost every other competition and sporting event held within the region. Both schools were part of some of the earliest competitions where the concrete canoes actually races down river courses to determine the winner.

New Haven came forward with a strong entry. With an attractive boat and an enthusiastic young team the "other UNH" came to New Hampshire to showcase their hard work. They were one of a number of younger teams pushing the early leaders with strong showings in the earlier events and some new design modifications to the ribs to provide support when paddling. Their final position was also going to be determined by the race events. In the Northeast where the climate makes canoe conditioning and practice a event that takes considerable planning, the amount of time spent practicing, especially in make quick, tight turns the difference between winning and losing a race and even a competition.

Northeastern came out of the gate strong with a boat dedicated to Boston History. The boat finish, displays and presentation included recognition of the Freedom Trail and included a working cannon. With a strong showing entering the races, it appeared certain that they would be in the thick of the competition for the slots to Nationals until the first race event when tragedy struck. On the home stretch, the boat broke in the middle sending both paddlers into the shallow water. Competitors to the end, they recovered the severed boat and went to work trying to reconnect and patch the boat. Through hard work and quick thinking they were able to repair the cano and managed to go through a mandatory dunk test where a canoe has to show that even fully submerged it will still float. This test was passed, but the boat ultimately broke again before re-entering competition. 

Dartmouth was looking to build on some top five performances in 2008 and 2009. With a solid performance through the early challenges they pushed the leaders and like many others came down to the races. Mixing in some leaders from the junior class, they are looking to improve continuity within the program.                                                                                            

This year UNH was the host school as well as a competitor. With some bad luck earlier in the year, there was a period of time when it appeared that the host would not field a boat in their own event. The hard work of the canoe committee ultimate won out preparing a solid entry and making a strong showing on the water. With eleven competitors it was necessary to run three heats and a final race for four of the events. UNH earned their way to two of the four finals. One of the closest battles of the day occurred when UNH secured a third place finish in one of the finals by only 1/4 of a second. UNH distinguished themselves as a solid competitor and a first class host.

URI provided one of the most impressive visual demonstrations with a display and canoe art that were both creative and artistic. A series of pictures would be needed to truly appreciate the graphics on the canoe. The theme was Ramses the Great as one of the world's master builders with Egyptian symbolism throughout their displays, presentations, and canoe. They were quickly one of the earlier favorites, but with the strong competition, had to wait for the races to determine who would be going to Nationals.

Wentworth fielded a solid entry ready to challenge the other schools. After competing in the Nationals as recent as 2005, the last few years have included a 9th and 10th regional finish. This year's entry was dedicated to the USS Constitution for the 200th anniversary of the War of 1812. This year's canoe included a new hull design and a new approach to creating the molds.

All of these changes from previous designs kept them in the heart of the pack with the final order being decided during the race events.
WPI was one of the younger programs that showed a lot of heart. Some of the disadvantages to the younger programs or programs where there has been a break in continuity are the number of rules that include height of lettering, abbreviations, and a number of seemingly mundane rules that come with the program. Experience helps clarify the rules while younger programs often learn the hard way with small deductions throughout the process.
Amherst is a younger team with a lot of enthusiasm. After struggling for the last few years, this year's team stepped away from previous construction methods to chart a new course. Their 9 Million Carat entry payed homage to a glitch where their scale was stuck in the carat unit mode making it necessary to make some odd conversions to keep their project moving. Construction of the canoes is a complex process where the teams encounter many unanticipated problems and require quick thinking to return to a normal schedule. All of this while trying to complete one of the more challenging undergraduate fields of study, Civil Engineering.

  

With all the work done, all the judging complete, and the races concluded, it all came down to the final announcement. Tony Puntin, former regional ASCE Governor and current ASCE National Board member, further built the suspense with a brief discussion about the benefits of ASCE and the importance of younger engineers to continue as members as a vital tool in their career development.

UNH ASCE Student president Anabelle Allen and Head Judge Jeff Klein ended the suspense with the announcement of the top three teams and the final results. With an incredible performance, Laval University retained its standing as the leader of the Northeast Region. In a very tight battle the University of Massachusetts at Lowell beat out the University of Rhode Island to earn the second coveted spot to the National Competition. Congratulations to our regional winners and thanks to all of the competitors for such a strong field. Final congratulations to UNH for hosting an exceptional competition with a lot of fun for all of the competitors and spectators.

Thursday, April 19, 2012

It's all about the money for I-93 expansion | New Hampshire NEWS06

It's all about the money for I-93 expansion | New Hampshire NEWS06

ASCE National President Elect Greg Diloreto Visit

Yesterday ASCE National President Elect Greg Diloreto visited New Hampshire, meeting with several ASCE-NH Board members for lunch, visiting Portsmouth with views of the Portsmouth Naval Shipyard and the Memorial Bridge project in the afternoon and closing the evening by providing the keynote speech for the Order of the Engineer ring ceremony at the University of New Hampshire.

ASCE National President-Elect Greg Diloreto and ASCE-NH President Ken Milender are pictured with the Memorial Bridge in the background yesterday. The center span of the bridge was floated out earlier in the year, Pictured is the Kittery section of the bridge.
In addition to the key note speech, members of the engineering societies spoke about the pride and ethics of being a professional engineer. University of New Hampshire professors provided a history of the ring ceremony. The Order of the Engineer dates back to a bridge disaster in Quebec City, Canada, where the engineer of record allowed his pride to cloud his judgement leading to the deaths of many construction workers when he was repeatedly cautioned about issues in the field, but fielded to heed the warnings ultimately leading to a dramatic failure of the bridge. The rings are symbolic of earlier rings that were made from the steel from the failed bridge. The rings are worn on the little finger of the engineer's dominant hand as a continuous reminder of the responsibilities we each share to protect the public even above our duties to ourselves and our reputations.



Tuesday, April 17, 2012

UNH is Hosting the Concrete Canoe Competition this Weekend!

2-4:30pm: Registration and set up in Morse Hall (parking area 1)
4:30-5:30pm: Cross Section/ Display Judging in Morse Hall
5:30-6pm: 
Captain’s Meeting in Morse Hall
6-9pm: Presentations and Pizza dinner in Spaulding Hall Rm 120    
7-9am: Arrival at Ayer’s Lake Campground and Canoe setup with Breakfast
9-11am: Display Judging and Sink Test
11am-5pm: Racing*
      * Lunch will be served at noon
5-8pm: Dinner back at the UNH's dining hall (or wherever you choose)
8-9pm: Brief Awards Ceremony with hot beverages and dessert in DeMerrit Hall Rm 112 with guest speaker from ASCE 

     (parking area 2) 

My Turn: In Boscawen, roundabout trouble galore | Concord Monitor

My Turn: In Boscawen, roundabout trouble galore | Concord Monitor

Bass sees a time for compromise - | Concord Monitor

Bass sees a time for compromise -  | Concord Monitor