Editing Harvard Bridge (section)

==Maintenance and events==
[[File:Harry Houdini jumps from Harvard Bridge, Boston, Massachusetts, 1908 - John H. Thurston, stereopticons LCCN2015650990 - restoration.jpg|thumb|left|300px|[[Harry Houdini]] before he jumped from the bridge 1908]]

In 1898, {{convert|3|ft|m sm|adj=mid|sp=us|-wide}} bicycle lanes were installed next to each curb.<ref name=haer3 />  In 2011 (113 years later), the City of Boston finally connected these lanes to its own bike lanes.<ref name=bglanes>{{cite news |title = Mass. Ave, BU Bridge bike lanes completed |first = Johanna| last = Kaiser |url = http://www.boston.com/yourtown/news/back_bay/2012/01/mass_ave_bu_bridge_bike_lanes.html |newspaper = Boston Globe |publisher = New York Times Co. |date= January 6, 2012 |access-date= March 20, 2012 |quote=The city installed bike lanes on the northbound and southbound lanes between Huntington Avenue and the Harvard Bridge, connecting them to existing bike lanes, just before the start of the new year. }}</ref>

A marker near the southeast end of the bridge memorializes one of [[Harry Houdini]]'s "well known escapes", during which he jumped from the bridge on May 1, 1908. (Other sources give the date as April 30, 1908.)<ref name=clinger>{{cite book
|last=Clinger
|first=Julia
|title=It Happened in Boston
|url=https://archive.org/details/ithappenedinbost00clin
|url-access=registration
|edition=1st
|date=June 1, 2007
|publisher=TwoDot
|isbn=978-0-7627-4134-2
|pages=[https://archive.org/details/ithappenedinbost00clin/page/61 61]–63
}}
</ref>

The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced.  The draw was elevated slightly and the trolley rails were replaced as well.<ref name=nyt1906>{{cite news
 | title = Famous Harvard Bridge Unsafe| url = https://timesmachine.nytimes.com/timesmachine/1909/07/16/101818048.pdf| work = New York Times | date = July 16, 1909 | access-date = March 20, 2012 | quote=The famous Harvard Bridge connecting Cambridge and Boston was declared to be unsafe in a report made to-day by a commission of Boston and Cambridge engineers, and announcement was made that work would be started on Monday next to strengthen the structure.  The commission finds that all of the iron and steel beams of the bridge, which is nearly three-quarters of a mile long, will have to be replaced by new ones, at the same time the draw will be elevated slightly, and new surfacing will be put on.  The Boston elevated railway company, which operates its cars across the bridge, is ordered to install new rails and new supports. <!-- copyright has expired on this 1909 article --> }}</ref>

When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure.  They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails.<ref name=haer3 />  Structural steel hangers replaced wrought iron.  The swing span was converted into two {{convert|75|ft|m sm|adj=on|sp=us}} fixed spans the same width as the rest of the bridge.  The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.<ref name=haer4>HAER, p.4</ref><ref name=tech044>{{cite news | title = Commonwealth Begins Work on Harvard Bridge | url = http://tech.mit.edu/archives/VOL_044/TECH_V044_S0154_P005.pdf | work = The Tech | publisher = [[Massachusetts Institute of Technology]] | location = [[Cambridge, Massachusetts]] | date = October 3, 1924 | page = 5, col. 4 | access-date = April 27, 2009 | archive-date = September 24, 2012 | archive-url = https://web.archive.org/web/20120924125348/http://tech.mit.edu/archives/VOL_044/TECH_V044_S0154_P005.pdf | url-status = dead }}</ref>

Heavy traffic at the [[Massachusetts Avenue (Boston)|Mass Ave]] and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931.<ref name=haer5>HAER, p. 5</ref>

The bridge was formerly referred to as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it.  This decking was replaced in 1949 with {{convert|3|in|mm sm|adj=on|sp=us}} concrete-filled "I-beam lok" grating topped with a {{convert|2.25|in|mm sm|adj=on|sp=us}} thick bituminous wearing surface.  At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks.  The trolley car poles were reused for street lights.  Ramps between the bridge and the under-construction [[Storrow Drive]] were added.<ref name=haer5 />

The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.<ref name=haer5 />  The fifteen expansion dams were replaced or repaired in 1969.<ref name=haer6>HAER, p.6</ref>

===Engineering study, 1971–1972===
[[File:Harvard Bridge Art.JPG|thumb|The Harvard Bridge is decorated with both serious and whimsical works of art.]]
An engineering study was performed by the Metropolitan District Commission (later merged into the [[Department of Conservation and Recreation (Massachusetts)|Department of Conservation and Recreation]]) in 1971–1972 due to complaints by bridge users of excessive vibration.<ref name=haer5 /><ref name=leet2>Leet, phase 2</ref>  The bridge was found to be understrength for its load.  Before the final study was complete, the recommendation was to place a load limit of {{convert|8|ST|MT|lk=on|sp=us}} per axle and a total of {{convert|15|ST|MT|sp=us}} per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger.  A {{convert|25|ST|MT|adj=on|sp=us}} limit was imposed.<ref name=leet3>Leet, phase 3</ref>

Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards.<ref name=leet2 />  The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.<ref name=leet3 />

The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge.  The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at [[AASHO]] HS-20.  Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards.<ref name=leet3 />  Detailed engineering calculations were included.<ref name=leet32>Leet, phase 3, appendices</ref>  The price was estimated at US$2.5 million to US$3 million<ref name=leet3 /> (US${{formatnum:{{Inflation|US|2500000|1972|r=-6}}}} to US${{formatnum:{{Inflation|US|3000000|1972|r=-6}}}} with inflation<ref name=inflation-US />).

The action taken based on this study was to establish load restrictions on the bridge, {{convert|15|ST|MT|sp=us}} in the outer lanes, {{convert|25|ST|MT|sp=us}} on the inner lanes.  This was expanded in 1979 to a flat limit of {{convert|15|ST|MT|sp=us}} on the whole bridge.<ref name=haer8>HAER, p.8</ref>

===Superstructure replacement, 1980s===
After the failure of the [[Mianus River Bridge]] at [[Greenwich, Connecticut]] in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans.<ref>{{cite news
  | last = Keane
  | first = Tom
  | title = It's the Engineering, Stupid
  | work = Boston Globe Magazine
  | publisher = [[Boston Globe]]
  | date = September 10, 2006
  | url = http://www.boston.com/news/globe/magazine/articles/2006/09/10/its_the_engineering_stupid/
  | access-date = September 11, 2006 }}</ref><ref>{{cite news
  | agency = [[United Press International]]
  | title = AROUND THE NATION; Boston's Harvard Bridge Closed to Heavy Trucks
  | work = The New York Times
  | date = July 6, 1983
  | url = https://www.nytimes.com/1983/07/06/us/around-the-nation-boston-s-harvard-bridge-closed-to-heavy-trucks.html
  | access-date = April 13, 2009 }}</ref>  Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14.  A few days later, all trucks and buses were banned from the bridge.<ref name=haer8 />

In 1986, a report was published containing the plan to replace the superstructure on the existing supports.  Alternatives considered were very similar to the [[#Engineering study, 1971-1972|1972 report]], and were similarly decided.<ref name=replacement7>Replacement, p.7</ref>  Structural modifications included an upgrade from four longitudinal girders to six of the same shape and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.<ref name=replacement>Replacement, p.4</ref>

Ramp "B", from southbound (Boston bound) bridge lanes to eastbound [[Storrow Drive]], caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues.  The MDC requested elimination of this ramp.  Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.<ref name=replacement910>Replacement, page 4-6</ref>

The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting.  In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.<ref name=replacment11>Replacement, p.11.  Note the use of the HAER document throughout this article.</ref>

Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.<ref name=replacement5>Replacement, page 5</ref>

The work would be done in two phases.  Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months.  Most of this effort would be spent on the underside of the bridge and would not affect existing traffic.  Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement.  Cost was estimated to be {{USD|20M}}<ref name=replacement5 /> (US${{formatnum:{{Inflation|US|20000000|1986|r=-6}}}} with inflation<ref name=inflation-US />).  Phase 1 finished in 1987, and Phase 2 in 1990.<ref name=globe1990>{{cite news
 | title = MASS. AVE. BRIDGE TO REOPEN FOUR LANES AFTER SEVEN YEARS
 | author = Ronald Rosenberg, Globe Staff
 | newspaper = Boston Globe
 | location = Boston, Massachusetts
 | date = September 12, 1990
 | page = 35 (METRO section)
 }}</ref>

<gallery caption="Before-and-after images" widths="225px" class="center">
File:Harvard Bridge, Spanning Charles River at Massachusetts Avenue, Boston ( Suffolk County, Massachusetts).jpg|Bridge viewed from the upstream Cambridge side in 1985.  Construction barrels restricting traffic from the outside lanes, and general wear and tear are visible (click on image to enlarge)
File:Harvard Bridge from Cambridge, 2009.jpg|Roughly the same view, in 2009.  Superstructure is in much better shape only 20 years after completion, than the 1985 superstructure was roughly 40 years after its most recent major work.
</gallery>
<gallery widths="225px" class="center">
File:Underside, centerline, 1985.jpg|Underside of the bridge in 1985.  Image shows how the bridge was originally built, and later modified, but before the superstructure was replaced.
File:Harvard Bridge, centerline, looking north, 2009.jpg|Underside of the bridge in 2009.  Image shows how the replacement superstructure was built, with six longitudinal girders, different bracing, etc.
</gallery>

===Subsequent events===
In the fall of 2014, the Charles River Conservancy announced that an anonymous donor would fund an upgrade of the street lights for both the roadway and both sidewalks on the bridge.<ref>{{cite web|url=https://www.bostonglobe.com/metro/2014/10/13/call-smoot-lighting-million-gift-will-brighten-mass-ave-bridge/5UehpL7Zk7YV9gWB3hb3KP/story.html|title=Smoot lighting: $2.5 million gift will brighten Mass. Ave. bridge - Metro - The Boston Globe|work=BostonGlobe.com|access-date=October 17, 2014}}</ref><ref>{{cite web|url=http://www.thecharles.org/2014/10/2-5-million-gift-will-shed-light-on-the-harvard-bridge-2/|title=$2.5 million gift will shed light on the Harvard Bridge|publisher=Thecharles.org|access-date=October 17, 2014|archive-date=October 22, 2014|archive-url=https://web.archive.org/web/20141022195250/http://www.thecharles.org/2014/10/2-5-million-gift-will-shed-light-on-the-harvard-bridge-2/|url-status=dead}}</ref> The new roadway and aesthetic lighting was installed in 2015, highlighting the smoot marks along the sidewalk. The design was selected after a competition won by [[Miguel Rosales]] of Rosales + Partners.<ref>{{Cite web |url=https://slice.mit.edu/2014/10/21/smoot-lights-harvard-bridge/ |title=Smoot Lighting to Set the Mood on Harvard Bridge |access-date=November 21, 2014 |archive-url=https://web.archive.org/web/20141129162140/https://slice.mit.edu/2014/10/21/smoot-lights-harvard-bridge/ |archive-date=November 29, 2014 |url-status=dead }}</ref><ref>{{cite news
  | last = Ramos
  | first = Nestor
  | title = $2.5 million gift will shed light on the Harvard Bridge
  | work = Boston Globe
  | publisher = [[Boston Globe]]
  | date = October 14, 2014
  | url = https://www.bostonglobe.com/metro/2014/10/13/call-smoot-lighting-million-gift-will-brighten-mass-ave-bridge/5UehpL7Zk7YV9gWB3hb3KP/story.html
  | access-date = October 22, 2014}}</ref><ref>{{cite news
  | title = With Smoot design, Harvard Bridge is the latest to shine
  | work = Boston Globe
  | publisher = [[Boston Globe]]
  | date = October 21, 2014
  | url = https://www.bostonglobe.com/opinion/editorials/2014/10/20/with-smoot-design-harvard-bridge-latest-shine/wjmtXBm32Zlt7ndXm9LHhO/story.html
  | access-date = October 22, 2014 }}</ref> The light posts were located {{convert|30|sm|ft m|sigfig=4}} apart.<ref>{{cite web|url=http://tech.mit.edu/V134/N54/smoot.html|title=Smoot legacy continues on Harvard Bridge - The Tech|publisher=Tech.mit.edu|access-date=November 20, 2014}}</ref>
"It will provide safe lighting for pedestrians and drivers, and the elements of design on the bridge will be pulled out and emphasized. It will become a really beautiful bridge," said Renata von Tscharner, founder and president of the Charles River Conservancy.<ref>{{cite web|url=http://www.bostonmagazine.com/news/blog/2014/09/02/massachusetts-avenue-bridge-light-project-donor/|title=An Anonymous Donor Is Bringing Light to the Mass. Ave. Bridge|publisher=Bostonmagazine.com|access-date=October 17, 2014|date=September 2, 2014|archive-date=October 21, 2014|archive-url=https://web.archive.org/web/20141021114037/http://www.bostonmagazine.com/news/blog/2014/09/02/massachusetts-avenue-bridge-light-project-donor/|url-status=dead}}</ref><ref>{{cite web|url=http://www.thecharles.org/2014/09/an-anonymous-donor-is-bringing-light-to-the-mass-ave-bridge/|title=An Anonymous Donor is Bringing Light to the Mass. Ave. Bridge|publisher=Thecharles.org|access-date=October 17, 2014|archive-date=October 22, 2014|archive-url=https://web.archive.org/web/20141022195245/http://www.thecharles.org/2014/09/an-anonymous-donor-is-bringing-light-to-the-mass-ave-bridge/|url-status=dead}}</ref>

===Separated bicycle lanes===

In November 2021, to improve bicycle safety, MassDOT initiated a separated bicycle lane pilot on the Harvard by placing cones to create two wide bicycle lanes. This reduced general purpose lanes from four to two over the bridge. Despite some hiccups involving vandalism, the pilot was deemed a success in the Fall 2022. MassDOT went on to hire Toole Design Group to engineer flex-post separated bicycle lanes, bus priority lanes, and new traffic signal phasing for the corridor. These changes were implemented just before 2023, and have been in place since. To this date, the Harvard Bridge remains one of the most popular cycling routes in New England, with an average of over 1,000 bicyclists in each direction per day.