Bridge Reconstruction Research Articles

The influence of the masticatory mucosa on the peri-implant soft tissue condition

Dr. Jan L. Wennstrom, Department of Periodontology, University of Goteborg, Medicinaregatan 12, S-413 90 Goteborg, Sweden.

Brow-Supported Spectacle Frames for Nasal Bridge Reconstruction and Other Deformities

To the Editor. —The points used to support conventional spectacle frames function well for most, but not all, patients. We describe a spectacle frame that can support lenses by using the brow and temporoparietal regions, thus avoiding the conventional pressure points. Its use for various temporary and permanent conditions is discussed. Methods and Materials. —The Multiframe spectacle (Fig 1) is constructed of lightweight plastic. The bridge portion of the frame is contoured to the forehead and is supported by the brow, thus no nasal pads are required. It has a swivel joint that suspends the lens rims forward and allows for rotation of each lens independently. The sides have a hinged joint and are angled inward to clamp the temporoparietal area of the head. There is no contact with the postauricular area. The Multiframe is available in only one size, and the back vertex distance and the geometric centers of

Electrification Of British Railways' East Coast Main Line: Civil Engineering Works, Hitchin to Doncaster

This Paper describes the contribution of the King's Cross office to the civil engineering design and construction activities associated with the electrification of the East Coast Main Line (ECML). It indicates the scope of the works to prepare the route between Hitchin and Doncaster for the full installation of the overhead traction equipment. Brief reference is made to the evolution of the proposals to extend the initial suburban electrification of the main line between King's Cross and Hitchin, completed in 1977. Standards and techniques for bridge reconstruction to obtain clearance, parapet raising and protection have been covered elsewhere and therefore the Paper concentrates on two particular bridges each considered of specific or unique interest. These are the replacement of an aqueduct and a scheme devised to enable three centre arches of a nine arch overbridge to be demolished and replaced by a single span capable of bridging four tracks. This latter scheme not only avoided the initially foreseen need for a complete reconstruction, involving considerable cost savings, but produced an enhancement in programming such that electric running from London to Leeds was achieved 14-months ahead of expectation.

Treatment of an early implant failure according to the principles of guided tissue regeneration (GTR).

The present case report demonstrates the application of guided tissue regeneration (GTR) in combination with antimicrobial therapy for the treatment of an early implant failure. This treatment approach both prevented further loss of bone as well as led to the regeneration of lost bone. By means of color-converted digital subtraction images, remodelling of the tissues adjacent to the defect was documented as early as one month postsurgically. The images demonstrated "bone-fill" in the apical portion of the defect and resorptive changes at the bone crest. This case report demonstrates that combined regenerative and antimicrobial therapy may be a successful treatment approach restoring osseointegration of dental implants following loss of bone due to infection. Continuously increasing bone-fill inside the defect was documented when comparing the radiograph obtained immediately before the GTR procedure and at months 1, 2, 4, 5 and 6 of the healing period, respectively. Clinical measurement obtained at the time of the surgery and at the time of the membrane removal confirmed the radiographic evidence of bone-fill by demonstrating new tissue resistant to probing in close contact to the implant surface at the site of the previous defect. Antimicrobial therapy included an antibiotic regimen during the 1st month of healing as well as topical rinses with an antiseptic (chlorhexidine) over the entire healing period of 6 months. As a result of this treatment approach, the implant was saved and could be used as an abutment for a bridge reconstruction.

Reconstruction of the swing bridge on the lower svir' lock

Reconstruction of the swing bridge on the lower svir' lock

Aseismic slip on the San Andreas Fault south of Loma Prieta

Two digital creepmeters installed within the San Andreas fault zone after the 18 Oct 1989 Loma Prieta main shock show less than 1 cm of post seismic right‐lateral slip in the four months following the earthquake. At Mt. Madonna road a 23 mm coseismic fracture slipped a further 3 mm after heavy rain, and at Nyland Ranch near San Juan Bautista the fault slipped approximately 9 mm starting 42 days after the main shock. If the current trend at Nyland Ranch persists, more than 2 cm of post seismic slip will develop by 1991. At both sites minor left‐lateral displacements occurred which are attributed to near‐surface soil effects. The abutments of the railroad bridge across the Pajaro River at Chittenden, which were extended by the 1906 earthquake, were not extended during the Loma Prieta event although they have evidently moved apart by more than 7 cm since bridge reconstruction in 1940. This corresponds to 10 cm of right‐lateral slip which could be related to M>5 events in mid‐century or could be due to aseismic slip at a mean rate of 2.1 mm/a. The absence of significant surface slip within the fault zone in the decades before and the months following the Loma Prieta event suggests either that near‐surface deformation is distributed over a wide zone or that a slip deficit remains. Several authors have proposed this region as a future location for M≈5 events.

Reconstruction of the skip bridge of a blast furnace with the use of an EDK 1000/1 crane

The enlargement of the engine rooms, the installation of trestles and conduits for placing the furnace stoves on draft, and the construction of other facilities have made it impossible to install large hoisting machinery between the blast furnaces and the stockhouse or to replace skip bridges with rigging systems such as are used at the Nizniy Tagil Metallurgical Combine. It must also be considered that during the reconstruction of a blast furnace and the auxiliary sections, an important precondition is providing for normal operation of the other furnaces in the shop. This is particularly true when the furnaces are arranged in a block or linear configuration.

Quantitative analysis of debris torrent hazards for design of remedial measures

Debris torrents, which are rapid flows of soil and organic debris down steep mountain channels, are a major natural hazard in many parts of British Columbia.A series of recent occurrences along the Squamish Highway, north of Vancouver, led the provincial government to initiate a systematic study of debris torrents in this area. This 2 year study involved hazard risk assessment and resulted in the design of a comprehensive system of remedial measures comprising debris retention barriers and basins, channel improvements and diversions, and the reconstruction of bridges. It was necessary in the course of this effort to formulate new design procedures covering the dynamic behaviour of debris torrents, as there was no accepted practical methodology suitable for Western Canadian conditions.This paper provides an approach to determining magnitude (volume of debris material involved), frequency, peak discharge, velocity, conditions for deposition, runout distance, behaviour in bends and run-up against barriers, and dynamic thrust and impact loadings. The procedures are based on some of the more practical concepts available in the specialized literature, supplemented by simple original theories and calibrated against several recent debris torrent events from British Columbia for which sufficiently detailed observational data exists. To be generally applicable, the procedures require a wider and more thorough calibration. They are presented here as working hypotheses that can be used as a guide to the assembly of additional data and provide a rational design tool to supplement the application of experience and judgement. Key words: debris torrents, debris flows, slope hazards, landslide dynamics, remedial measures, engineering design.

Timber Bridges: Benefits and Costs

Deterioration of bridges in Western Pennsylvania accelerated after the inception of the use of deicing agents two decades ago. These bridges were constructed primarily of reinforced concrete and steel with no provisions in their design for protection from deicing agents. These agents chemically attack unprotected steel and concrete and ultimately cause weakening of the bridge structure. The benefit of the resistance of timber to the effects of deicing agents led to the reconstruction of three highway bridges using modern timber design. Details of two cases of highway bridge reconstruction are presented: (1) A deck replacement over steel stringers; and (2) a beam and deck replacement using existing abutments. The case of replacement of a railroad overpass is also presented. A primary consideration in this project was the minimization of railroad service disruption time. This was accomplished by fabricating timber members on site to accommodate uncertain field conditions. In this case, the use of steel or concrete would have resulted in an unacceptably lengthy service disruption.

中耳手術におけるアパタイトの応用

A closed technique of the middle ear surgery for cholesteatoma has been widely used because an open method has disadvantage to form a wide cavity and debris accumulation. However, elimination of the bony bridge is sometimes necessary for complete removal or debridement of the cholesteatoma matrix. In such a procedure, it becomes important to reconstruct the bridge which can protects postoperative retraction of the ear drum and succeeding so-called pocket formation. For the purpose of bridge reconstruction, we try to use sintered hydroxyl apatite ceramic.Preceding the clinical application, an animal experiment was performed, that is, the apatite was embedded in the tibia of the rabbit and postoperative course was observed. The experiment revealed that the apatite did not cause inflamatory or foreign body reaction in the surrounding tissue and adhered strongly to the host bone and the covering soft tissue.Following this animal experiment, we applied the porous apatite with 55% of pore rate, the same as used in the animal experiment, to the middle ear surgery. The apatite plate has a curvature to fit the external canal wall. After trimming of the apatite plate, it was inserted to the site of removed bridge and covered by fascia at the canal side. Mastoid cavity was obliterated by collagen sponges.Our 1 and 1/2 years experience with the use of the apatite is limited to 16 cases. Although the follow-up on these cases was too short for final evaluation, the initial results showed a satisfactory condition without infection or extrusion. We propose that this material can be valuable in the reconstruction of bony defect in the external ear canal.

Modelling of Charles Bridge in Prague: numerical analysis and statistical simulation

The last reconstruction of the famous Charles Bridge caused that the bridge changed its structural behaviour. This resulted in excessive deflections and cracks. The aim of the present study was to understand the structural behaviour of the bridge under temperature loads. Finite element modelling in a combination with a statistical simulation was used respecting different materials and their interactions. Their variability is taken into account they are considered to be random variables. Statistical characteristics of a structural response (stresses and deflections) were calculated based on the advanced Monte Carlo simulation. Sensitivity analysis was also performed.

The distortion of autogenous cartilage grafts: Its cause and prevention

Summary 1.Autogenous cartilage as a grafting material for nasal bridge reconstruction has largely fallen into disuse because of the high incidence of distortion. An analysis of ninety-one of Professor T. P. Kilner's cases showed that about two-thirds warped to some extent within one or two weeks after operation, although the grafts had been freed from fibrous perichondrium before insertion. 2.Experiments in vitro demonstrated that in rib cartilage a state of tension exists in which the taut outer layer of cartilage acts as a skin which controls the tendency of the main mass to expand. 3.Distortion results from the contraction of the outer layer when the rib is so carved that the natural equilibrium is upset. In this the fibrous perichondrium plays little or no part. 4.The of the balanced has been introduced: if the distorting forces are balanced at all points along a cartilage graft as viewed in cross-section it will not warp. 5.Applying this principle, methods are detailed whereby stable grafts for nasal bridge reconstruction may be obtained. 6.Although the amount of carving permissible is limited, the shape and size of the costal margin cartilages are peculiarly suitable for nasal bridge grafts. 7.Forty-six grafts, carved according to the principle of the balanced cross-section, have been inserted during the past three years, and none has become distorted. 8.When used as described, autogenous rib cartilage is considered to be the material of choice in nasal bridge restoration.

Method of shaping a plastic implant for reconstruction of the nasal bridge.

Method of shaping a plastic implant for reconstruction of the nasal bridge.

The Reconstruction of the French National Railway Bridges

The Reconstruction of the French National Railway Bridges

Some Examples of the Reconstruction of Road Bridges in France

Some Examples of the Reconstruction of Road Bridges in France

Institution of Civil Engineers: Awards

THE following medal, premiums and prizes of the Institution of Civil Engineers have been awarded for the papers mentioned, which have been discussed, or publisired without oral discussion, during the session 1945–46. Baker Gold Medal: G. L. Groves, in recognition of his work in connexion with the Ilford Tabe. Coopers Hill War Memorial Prize: G. A. Maunsell, “Menai Bridge Reconstruction”. Telford Premiums: K. C. Appleyard and G. Curry, “Opencast Coal Production in Wartime”; R. F. Wileman and H. W. Clark, “The Measurement of the Discharges of the River-basins of the White Nile (Sudan) and None (Great Britain)”; M. R. James, “Renewal and Extension of Pumping Machinery for the Metropolitan Water Board”; A. E. Reid and F. W. Sully, “The Construction of the King Feisal Bridge and the King Ghazi Bridge over the River Tigris at Baghdad”; J. N. McFeeters, “Concrete Runways”; J. K. Fisher, Alfred Goode and C. E. Docker, “Some Problems in the Design and Construction of Large Airfields”; J. D. Atkinson and George Cardiacos, “The Reconstruction of the Diyala Weir”; Robert Struthers and J. W. Lovatt, “Construction of a Heavy-Duty Concrete Runway”; Rudolph Glossop and A. W. Skempton, “Particle-size in Silts and Sands”; C. H. Dobbie, “Some Sea Defence Works for Reclaimed Lands”. Manby Premium: Rowland Nicholas, “Highway Planning, with Particular Reference to Traffic Capacities”. Crampton Prize: C. T. Mitchell, “Some Economical Aspects of Modern Earthmoving Equipment”; George Graham and F. R. Martin, “Heathrow. The Construction of High-grade Quality Concrete Paving for Modern Transport Aircraft”. Trevithick Premiums': James Lorimer, “Some Uses of Explosives in Civil Engineering”; A. H. Toms, “Repairs to Railway Viaduct over London Road, Brighton, after Damage by Enemy Action in May 1943”. Indian Premiums: Sir Claude Inglis, “Training Works constructed in the Rupnarain River in Bengal-after Model Experiments-to Prevent Further Bank Erosion endangering the Bengal-Nagpur Railway Line Linking Calcutta with Bombay and Madras”; C. G. Sext6n, “The Construction of the Coronation Bridge over ijhe Tista River, North Bengal, India”; Philip Claxtori, “The Still-Water Pocket Principle”.

Reconstruction of Cardiff Bridge, by THOMAS H. MORRIS, A.M.I.Mech.E

Reconstruction of Cardiff Bridge, by THOMAS H. MORRIS, A.M.I.Mech.E

Discussion on the Reconstruction of Kenova Bridge

Discussion on the Reconstruction of Kenova Bridge

Closure to the Reconstruction of Kenova Bridge

Closure to the Reconstruction of Kenova Bridge

THE RECONSTRUCTION AND WIDENING OF ARPLEY BRIDGE, WARRINGTON. (INCLUDING APPENDIX AND PLATE)

THE RECONSTRUCTION AND WIDENING OF ARPLEY BRIDGE, WARRINGTON. (INCLUDING APPENDIX AND PLATE)