SESTO CALENDE

Double deck
rail-road bridge

The study aims to evaluate and guarantee the safety of the bridge by introducing reinforcement systems that increase its resistance, while preserving its original architectural appearance.

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  • Profile type: Riveted composed profiles

  • External bonds: Steel supports

  • Masonry: Abutments and piers

Total Weight:

  • 5790t

  • Steel Structure: 2906t

  • Concrete Slabs: 1674t

  • Dead Loads:1210t

  • Total Length: 263,80m

  • Span: 82,4m

  • Span: 99m

  • Span: 82,4m

  • Trusses Spacing: 9,16m

  • Trusses Height: 14,30m

REALIZED ACTIVITIES

  • Structural analysis and checks Ante/Post Operam

  • Design of steel truss reinforcements

  • Batimetric survey with Marine Drone Multibeam Sonar Technology

Structural Analysis

STATIC AND SEISMIC ANALYSIS
The effects due to permanent, variable, traffic and seismic actions were taken into account, maximizing the stresses on all structural elements with the use of finite element software (FEM).

Static Analysis:
DISPLACEMENTS
Results:

Displacements are evaluated to verify not only
the deformability of the bridge but also the quality
of the numerical model.

Static Analysis:
DISPLACEMENTS
Dead Load Displacements

Due to the Dead Loads the main truss structure
has a maximum displacement in the
central span of approximately 27 mm.

MAX DISPLACEMENT

Static Analysis:
AXIAL FORCES
Design combination:

In the design combination both the
road load and the railway load
act simultaneously as principal.

Static Analysis:
AXIAL FORCES
Results:

MAX TENSION
MAX COMPRESSION

Seismic Analysis:

It is carried on by linear (modal) dynamic analysis
with response spectrum, through which actions
are determined starting from the calculation
of the periods and vibration modes of the structure.

Seismic Analysis:
VIBRATION MODES:
Modal Analysis Results:

Vibration mode 1
Period = 1,12 s
Participating mass (Y Direction): 15,90 %

Seismic Analysis:
VIBRATION MODES:
Modal Analysis Results:

Vibration mode 2
Period = 1,02 s
Participating mass (Y Direction): 61,65 %

Seismic Analysis:
VIBRATION MODES:
Modal Analysis Results:

Vibration mode 3
Period = 0,99 s
Participating mass (X Direction): 53,27 %

Seismic Analysis:
VIBRATION MODES:
Modal Analysis Results:

Vibration mode 10
Period = 0,32 s
Participating mass (Z Direction): 67,88 %

Design

OF STRUCTURAL REINFORCEMENTS
The main criteria was to leave the architectural aspect and the structural concept unchanged. The profiles were reinforced by inserting new steel plates or profiles, in order to increase resistance and stability to satisfy the checks.

In order to preserve the original architectural design
of the bridge and within the existing architectural constraints,
bolts with specific technical and aesthetic characteristics
were designed and selected.

Cross Beams Reinforcement Design

Reinforcement to increase the inertia and strength
of the upper crossbeams, intermediate crossbeams (road surface),
lower crossbeams (rail surface). Specific design according to the
characteristics of the existing beam and its stresses.

Upper Beams Reinforcement Design

Design of reinforcement intervention aimed at increasing
girder strength and improving the connection between
riveted composite profiles, limiting overall instability.

Diagonals Reinforcement Design

Reinforcement design included diagonal elements
subject to compression, improving the connection
between riveted composite profiles and limiting
the overall instability of the involved elements.

Uprights Reinforcement Design

The design of the reinforcement is aimed
at increasing the inertia and strength of the upright
and its specific design increases he overall section
of the beam while decreasing its instability.

Lower Beams Reinforcement

It was necessary to study specific solutions related to
several problems encountered simultaneously along
the same element. Increasing the inertia and strength
of the beam, improving the connection between the
composite profiles, and overall reducing the
instability of the compressed elements.

Cross Bracings Reinforcement Design

The specific design of the bracing system is aimed at increasing
the inertia and strength of the beam by doubling he section
of the element, with a corresponding increase in strength while
guaranteeing the stiffness necessary for the overall system.

Bathymetric survey

The knowledge of bathymetry is important
for a wide variety of uses:
for ETS it’s fundamental in projects for
the safety of road and railway infrastructure
along the coastline and river.

Marine Drone

During the survey carried out by the OTTER (USV)
it’s possible to check the DSM real-time trough Qinsy software
and therefore to provide a covering data
of the whole seabed at the same time.
The data are processed and returned in a 3D model
consisting of the union of georeferenced points.
This output allows to make correct evaluations
about seabed morphology and accurate assessments such as:

  • morphology of the riverbed

  • presence of foreign bodies

  • calculation of excavation and filling volumes

  • analysis of the coastal erosion

OTTER (USV)

INTEGRATED DATA IN A SINGLE DIGITAL ENVIRONMENT
By combining  OTTER (USV) with Bulti-beam Sonar WBMS
for a bathymetry survey and integrating the data obtained
with a topographic survey, we obtain a 3D reconstruction of
both the surface above the sea and below the sea.

B-SHAPE

The acquired data is used for study, material characterization,
and design solutions to strengthen the infrastructure and
mitigate the erosion effect near the line.
All acquired data, engineering a geological analysis
are integrated into our innovative  B-SHAPE software.