Oral history of British science
Parsons, Michael (Part 9 of 14). An Oral History of British Science
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Interviewee's home, Sidmouth
Parsons, Michael, 1928- (speaker, male)
Lean, Thomas (speaker, male)
Part 9: Further remarks on Severn Bridge: followed from weight reduction in Forth Bridge; big changes in use of plated box structure for deck and in towers; first use of box girder on suspension bridges; stability in wind conditions; use of similar box deck on Humber Bridge and many of worlds other longest bridges; advantages of box deck, wind stability, ease of maintenance; [05:25] MP leaving site after opening but returning to complete financial settlements; disagreements with contractor over length of time taken to finish bridge; recognition of work on bridge, winning the McRobert award with Rolls Royce, tea at Buckingham Palace; celebration of completion of later Humber Bridge; MP mixed feelings over Severn Bridge, MP doing outline design but not detailed design due to office politics involving Gilbert Roberts and Bill Brown, enjoying relaxing atmosphere on site and with family; Bill Brown and MP comparative backgrounds. [12:30] Remarks on: story about MP return to office in London, meeting Gilbert Roberts and Bill Brown in corridor; FFP awarded contract for first Bosporus Bridge; Gilbert Robert's retirement in late 1960s, leaving Bill Brown as partner in charge of Bosporus Bridge, with MP as designer; 1970 bridge collapses, division of related design work between Bill Brown and Gilbert Roberts; MP detailed design of Bosporus Bridge and managing of contract documents. [16:25] Story about Turkish government demanding 25 copies of the complete calculations of the Bosporus Bridge design: rejection of MP idea of providing a summary; logjam of FFP offices with copy duties; first occasion when a client was presented with complete calculations; MP valuing experience as a chance to check calculations. [19:00] Remarks on Bosporus Bridge: selection of contractor, opportunity for American alternative truss design bid; Cleveland Bridge and Hochtief assigned as contractors; work share arrangements between nations contributing to finance of bridge, anecdote about Bill Brown taking Turkish officials shopping in Milan on a factory inspection visit; Ken Hyatt and MP visit to foundations and decision to alter anchorage; advisory board of bridge experts to oversee design; Bill Brown being dispatch to Turkey as resident engineer, in wake of 1970 bridge collapses. [26:00] Story about very busy day of crowds on the bridge opening in October 1973. [29:03] Remarks on: MP feelings about bridge completion, culmination of long work; description of Bosporus Bridge site in Istanbul, designed to connect Europe and Asia; location opposition to Bosporus Bridge; description of Bosporus Bridge; economic necessity of bridge due to ferry bottlenecks. [34:05] Discussion of process of designing Bosporus Bridge: bridge engineers fitting small bridges into road plans; selection of site for bridge by short distance and good foundations; similarity of Bosporus bridge to Severn and Forth Bridge; process of turning concept into a design for fabrication; origin of general concept in previous examples, American Society of Civil Engineers book on George Washington Bridge; [38:30] Remarks on computing: MP never using a computer personally at work; previous methods for analysing designs using mathematical methods and a slide rule; contractor's use of computer on Severn Bridge for calculations involved in hanging of deck; FFP starting to use computers for analysis with help of Dr Brotton from Manchester University; use of computers to analyse load on bridge; computer use on calculations for Bosporus Bridge by Walter Brown. [44:50] Remarks on: design teams, MP doing Forth Bridge calculations, Walter Brown doing calculations later, assistants doing detailed drawings; advantages of shallow box suspension designs having low stresses, compared to previous truss designs; use of shallow box on non-suspension bridges requiring extra stiffening; additional safety factor of using a suspension bridge design with a box girder. [48:30] Remarks on working for FFP: sequence of offices around London, IIddesleigh House office near St James Park Station, 110 Victoria Street, join offices with Mott, Hey and Anderson, FFP main bridge office in Alliance House in Caxton Street; office politics, MP finding niche during Bosporus Bridge building. [52:15] Anecdote about MP relationship with Gilbert Roberts and Bill Brown, and MP reputation for safe design. [55:00] Comments on office politics and MP relationship with Bill Brown and Gilbert Roberts: mutual respect; Gilbert Roberts and Bill Brown relationship; MP good relations with Bill Brown during Bosporus Bridge; Gilbert Roberts cautious side to personality; breakdown of relationship between Bill Brown and MP during design of Second Bosporus Bridge; MP meeting with senior partner Jack Edwards, prior to Bill Brown's resignation; MP not seeing Bill Brown after resignation; no FFP staff invited to opening of Second Bosporus Bridge; damage to FFP reputation after 1970s collapses; anecdote about Mott Hay and Anderson using Royal Commission Report into Bridge Collapses to influence potential clients away from selecting FFP. [1:02:50] Comments on 1970 collapse of Milford Haven Bridge: description of collapses of bridge during construction; MP discussion with Bristol Aircraft engineers, who were surprised at crudity of bridge analysis; one off nature of bridge design; innovative nature of box girder bridges and difficulty analysing structures. [1:08:00] Comments on 1970 Yarra bridge collapse: description of bridge; description of redesign of deck of bridge by client; site staff decision to remove bolts to flatten out buckles in plating of deck; death of deputy engineer Peter Crossley, who had worked with MP on Severn bridge design; description of collapse of bridge after bolts were removed, destruction of canteen under bridge; Royal Commission into collapse; disagreement between Bill Brown and Yarra resident engineer Donald McIntosh, and replacement with a road engineer; Royal Commission finding that FFP mainly responsible for collapse; [1:15:25] contractual responsibility on contractor during construction; unconventional design causing problems for contractors; lessons learned from collapses; damage to FFP, death of Gilbert Roberts; [1:17:40] MP never reading report, conclusions of Royal Commission; reactions in FFP office; Royal Commission member Shirley Smith, who had worked with Oleg Kerensky; [1:20:15] MP opinions on bridge collapse, original design suitable, complications of erecting the modified bridge design; lack of understanding of how bridge would behave; generous safety margins in finished structures; problems understanding stresses on structures during construction; [1:25:10] suspension bridges, such as Tancarville Bridge, extra safety factors; stresses on bridge from load paths during cantilevering structures out; anecdote about MP discussion over load paths with consultants Flint and Neil; British Standards rules on erection allowing higher stress during construction; Merrison committee to establish standards for collapse loads for plates under compression; Forth Bridge tests on truss members and tower models. [1:30:50] Comments on: MP reactions to bridge collapses in 1970s; MP reassured by testing and safety of his own designs, concerns over Severn Bridge towers; Bill Brown's assignment to Bosporus Bridge after bridge collapses; Bill Brown's design of Yarra and Milford Haven Bridges; anecdote about an engineer leaving FFP due to disagreements with Bill Brown; Bill Brown responsibility for bridge collapses, Gilbert Roberts and Bill Brown relationship in bridge design.
Interview with bridge designer and structural engineer Michael Parsons